Etymology dictionary
ir- — irreverence (n.)
ir-
assimilated form of the two Latin prefixes in- "not," or "in" (see in-) before -r-.
IRS
also I.R.S., initialism (acronym) of Internal Revenue Service, U.S. federal government tax collection agency, attested by 1954. The office dates to 1862; name changed 1953 from Bureau of Internal Revenue.
ire (n.)
c. 1300, from Old French ire "anger, wrath, violence" (11c.), from Latin ira "anger, wrath, rage, passion," from PIE root *eis- (1), forming various words denoting passion (source also of Greek hieros "filled with the divine, holy," oistros "gadfly," originally "thing causing madness;" Sanskrit esati "drives on," yasati "boils;" Avestan aesma "anger;" Lithuanian aistra "violent passion").
Old English irre in a similar sense is unrelated; it is from an adjective irre "wandering, straying, angry," which is cognate with Old Saxon irri "angry," Old High German irri "wandering, deranged," also "angry;" Gothic airzeis "astray," and Latin errare "wander, go astray, angry" (see err (v.)).
ireful (adj.)
c. 1300, from ire (n.) + -ful. Related: Irefully.
I.R.A. (2)
also IRA, initialism (acronym) for individual retirement account, attested from 1974.
I.R.A. (1)
also IRA, 1921, initialism (acronym) for Irish Republican Army, the full name of which attested from 1919.
Ira
masc. proper name, from Hebrew, literally "watchful," from stem of 'ur "to awake, to rouse oneself."
iracund (adj.)
"angry, inclined to wrath," 1707, from Late Latin iracundus, from ira "anger, wrath, rage, passion" (see ire (n.)). Related: Iracundulous (1765).
Iran
country name, from Persian Iran, from Middle Persian Ērān "(land) of the Iranians," genitive plural of ēr- "an Iranian," from Old Iranian *arya- (Old Persian ariya-, Avestan airya-) "Iranian", from Indo-Iranian *arya- or *ārya-, a self-designation, perhaps meaning "compatriot" (see Aryan).
In English it began to be used 1760s, by orientalists and linguists (Alexander Dow, William Jones), in historical contexts, and usually with a footnote identifying it with modern Persia; as recently as 1903 "Century Dictionary" defined it as "the ancient name of the region lying between Kurdistan and India." In 1935 the government of Reza Shah Pahlavi requested governments with which it had diplomatic relations to call his country Iran, after the indigenous name, rather than the Greek-derived Persia.
Iranian (adj.)
1788, "of or pertaining to (ancient) Persia," from Iran + -ian. From 1839 in reference to the language. As a noun, "an inhabitant of Persia" (1792), later "the language of Persia" (1850). Iranic (adj.) is from 1847.
Iraq
country name, 1920, from an Arabic name attested since 6c. for the region known in Greek as Mesopotamia; often said to be from Arabic `araqa, covering notions such as "perspiring, deeply rooted, well-watered," which may reflect the desert Arabs' impression of the lush river-land. But the name might be from, or influenced by, Sumerian Uruk (Biblical Erech), anciently a prominent city in what is now southern Iraq (from Sumerian uru "city"). Related: Iraqi (attested in English from 1777, in reference to regional Mesopotamian music or dialects).
irascible (adj.)
late 14c., from Old French irascible (12c.) and directly from Late Latin irascibilis, from Latin irasci "be angry, be in a rage," from ira "anger" (see ire).
irascibility (n.)
irate (adj.)
1838, from Latin iratus "angry, enraged, violent, furious," past participle of irasci "grow angry," from ira "anger" (see ire).
Ireland
12c. in Anglo-Norman, a Germanic-Celtic hybrid, with land (n.) + Celtic Eriu (see Irish (n.)).
Irene
fem. proper name, from French Irène, from Latin Irene, from Greek Eirēnē, literally "peace, time of peace," a word of unknown etymology.
irenic (adj.)
"promoting peace," 1854, from Greek eirēnikos, from eirēnē "peace, time of peace," a word of unknown etymology. Earlier as irenical (1650s). Irenics is from 1834, originally a branch of theology.
irenology (n.)
"study of peace," 1974, from Greek eirēnē "peace" (which is of unknown etymology) + -ology. Related: Irenological.
Irgun
militant Zionist organization, 1946, from Modern Hebrew, literally "organization," in full Irgun Zvai Leumi "national military organization."
iris (n.)
late 14c. as the name of a flowering plant (Iris germanica); early 15c. in reference to the eye membrane, from Latin iris (plural irides) "iris of the eye; iris plant; rainbow," from Greek iris (genitive iridos) "a rainbow;" also "iris plant" and "iris of the eye," a word of uncertain origin, traditionally derived from PIE root *wei- "to bend, turn, twist."
Iris was the name of the minister and messenger of the Olympian gods (especially of Hera), visibly represented by the rainbow (which was regarded as the descent of a celestial messenger). From the oldest parts of the Iliad the word is used of both the messenger and the rainbow.
The eye region was so called (early 15c. in English) for being the part that gives color to the eye; the Greek word was used of any brightly colored circle, "as that round the eyes of a peacock's tail" [Liddell & Scott]. Another sense in Middle English was "prismatic rock crystal." Related: Iridian; iridine.
Irian
Indonesian name for New Guinea, said to mean literally "cloud-covered."
iridescent (adj.)
1784, literally "rainbow-colored," coined from Latin iris (genitive iridis) "rainbow" (see iris). The verb iridesce (1868) is a back-formation. Related: Iridescently.
iridescence (n.)
1799, from iridescent + -ence. Related: Iridescency (1799).
iridium (n.)
silver-white metallic element, 1804, coined in Modern Latin by its discoverer, English chemist Smithson Tennant (1761-1815) from Greek iris (genitive iridos) "rainbow" (see iris) + chemical ending -ium. So called "from the striking variety of colours which it gives while dissolving in marine acid" [Tennant]
Irish (n.)
c. 1200, "the Irish people," from Old English Iras "inhabitant of Ireland." This is from Old Norse irar, which comes ultimately from Old Irish Eriu (accusative Eirinn, Erinn) "Erin." The reconstructed ancestry of this derives it from Old Celtic *Iveriu (accusative *Iverionem, ablative *Iverione), perhaps (Watkins) from PIE *pi-wer- "fertile," literally "fat," from root *peie- "to be fat, swell" (see fat (adj.)).
From mid-15c. in reference to the Celtic language spoken in Ireland. Some Middle English forms of the word suggest influence of (or punning on) Old French irais, irois "wrathful, bad-tempered" (literally "ire-ous") and Irais "Irish."
Meaning "temper, passion" is 1834, American English (first attested in writings of Davy Crockett), from the legendary pugnacity of the Irish. Irish-American (n.) is from 1816 (as an adjective from 1820). Wild Irish (late 14c.) originally were those not under English rule; Black Irish in reference to those of Mediterranean appearance is from 1888.
Irishism (n.)
1734, from Irish (adj.) + -ism.
Irish (adj.)
c. 1200, Irisce, "of Irish nationality;" see Irish (n.). From 1580s as "Irish in nature or character." Irish stew is attested from 1814; Irish lace is from 1851; Irish coffee is from 1950.
Before 19c. often meaning "contradictory." In later use often in mocking or pejorative phrases, such as Irish apricot "potato," Irish daisy "common dandelion." Compare Dutch. Irish luck is by 1814, originally an ironic phrase indicating mischance or something done by means other than luck.
Irishman (n.)
c. 1200, from Irish (adj.) + man (n.).
Irishry (n.)
"people of Ireland, the Irish people conceived as a company or body," late 14c., from Irish + -ry.
Irishwoman (n.)
c. 1200, from Irish (adj.) + woman (n.).
irk (v.)
early 15c., irken, "to trouble (someone), disturb, hinder, annoy;" earlier "be lax, slow, or unwilling (in doing something); be displeased or discontented" (early 14c.); "be weary of, be disgusted with" (c. 1400); of uncertain origin, perhaps from Old Norse yrka "to work" (see work (v.)).
Watkins suggests it is related to Old Norse yrkja "work." Middle High German erken "to disgust" also has been suggested. A Middle English adjective, irk, meaning "weary, tired, bored; distressed, troubled; troublesome, annoying," is attested from c. 1300 in Northern and Midlands writing; it is sometimes said to be from the verb, but it is older, and Middle English Compendium says this is probably Celtic, and compares Old Irish arcoat "he injures," erchoat "harm, injury."
irksome (adj.)
"bothersome, troublesome, annoying," early 15c., from irk + -some (1). Related: Irksomely; irksomeness.
Irma
fem. proper name; see Emma.
ironic (adj.)
1620s, "pertaining to irony," from Late Latin ironicus, from Greek eironikos "dissembling, putting on a feigned ignorance," from eironeia (see irony). Related: Ironical (1570s); ironically.
iron (n.)
Middle English iron, iren, yron, from Old English iren, variant (with rhotacism of -s-) of isen, later form of isern, isærn "the metal iron; an iron weapon or instrument," from Proto-Germanic *isarn (source also of Old Saxon isarn, Old Frisian isern, Old Norse isarn, Middle Dutch iser, Old High German isarn, German Eisen).
This perhaps is an early borrowing of Celtic *isarnon (compare Old Irish iarn, Welsh haiarn), which Watkins suggests is from PIE *is-(e)ro- "powerful, holy," from PIE *eis "strong" (source also of Sanskrit isirah "vigorous, strong," Greek ieros "strong"), on the notion of "holy metal" or "strong metal" (in contrast to softer bronze).
Both an adjective and a noun in Old English, but in form an adjective. The alternative isen survived into early Middle English as izen. In southern England the Middle English word tended to be ire, yre, with loss of -n, perhaps regarded as an inflection; in the north and Scotland, however, the word tended to be contracted to irn, yrn, still detectable in dialect.
Chemical symbol Fe is from the Latin word for the metal, ferrum (see ferro-).
The meaning "metal device used to press or smooth clothes" is from 1610s. The meaning "golf club with an iron head" is by 1842. To have (too) many irons in the fire "to be doing too much at once" is from 1540s. Iron lung "artificial respiration tank" is from 1932. The iron crown was that of the ancient kings of Lombardy, with a thin band of iron in the gold, said to have been forged from a nail of Christ's Cross.
Iron horse "railroad locomotive" is from an 1839 poem. Iron maiden, instrument of torture, is from 1837 (probably translating German eiserne jungfrau). The unidentified French political prisoner known as the man in the iron mask died in the Bastille in 1703. In British history, Wellington was called the Iron Duke by 1832.
iron (v.)
c. 1400, irenen, "to make of iron," from iron (n.). Meaning "shackle with irons" is from 1650s. Meaning "press clothes" (with a heated flat-iron) is recorded from 1670s. Related: Ironed; ironing.
ironing (n.)
"act of pressing and smoothing clothes with a heated flat-iron," 1725, verbal noun from iron (v.). Ironing-board attested from 1762.
irons (n.)
"iron shackles or fetters," mid-14c., plural of iron (n.).
Iron Age
1590s, originally, as in Greek and Roman mythology, the last and worst age of the world; the archaeological sense of "period in which humans used iron tools and weapons" is from 1866 (earlier in this sense iron period, 1847).
iron-bound (adj.)
late 14c., from iron (n.) + bound (adj.1). Figurative use from 1807.
ironclad (adj.)
1852 of knights, 1861, of warships, American English, from iron (n.) + clad. Figuratively, of contracts, etc., "very rigid or strict, allowing no evasion or escape," from 1884. As a noun meaning "iron-clad ship," it is attested from 1862.
Iron Cross
from German eiserne kreuz, instituted 1813 by Frederick Wilhelm III of Prussia, originally for distinguished military service in the wars against Napoleon.
iron curtain (n.)
1794, the name of a fire-protection device to be used in theaters, a literal iron curtain; see iron (n.) + curtain (n.).
From 1819 in the figurative sense "impenetrable barrier." In reference to the Soviet occupation of Eastern Europe, famously coined by Winston Churchill March 5, 1946, in speech at Westminster College, Fulton, Missouri, but it had been used earlier in this context (for example by U.S. bureaucrat Allen W. Dulles at a meeting of the Council on Foreign Relations, Dec. 3, 1945). The phrase had been used in the sense of "barrier at the edge of the sphere of influence of the Soviet Union" from 1920. During World War II, Goebbels used it in German (ein eiserner Vorhang) in the same sense. But its popular use in the U.S. dates from Churchill's speech.
iron-gray (adj.)
Middle English, from Old English isengræg; see iron (n.) + gray (adj.). The color of freshly broken cast iron.
irony (n.)
"figure of speech in which the intended meaning is the opposite of the literal meaning" (usually covert sarcasm under a serious or friendly pretense), c. 1500, from Latin ironia, from Greek eironeia "dissimulation, assumed ignorance," from eiron "dissembler," perhaps related to eirein "to speak," from PIE *wer-yo-, suffixed form of root *were- (3) "to speak" (see verb). Used in Greek of affected ignorance, especially that of Socrates, as a method of exposing an antagonist's ignorance by pretending to modestly seek information or instruction from him. Thus sometimes in English in the sense "simulated ignorance."
For nuances of usage, see humor (n.). In early use often ironia. Figurative use for "condition opposite to what might be expected; contradictory circumstances; apparent mockery of natural or expected consequences" is from 1640s, sometimes distinguished as irony of fate or irony of circumstances. Related: Ironist. A verb ironize "speak ironically" is recorded from c. 1600.
irony (adj.)
"of or resembling iron," late 14c., from iron (n.) + -y (2).
ironmonger (n.)
also iron-monger, "dealer in iron-ware," mid-14c. (mid-12c. as a surname), from iron (n.) + monger (n.). Early forms also include ismongere, irenmanger, iremonger. A street named Ysmongeres lane is attested in London from c. 1215. Related: Ironmongery.
iron-on (adj.)
1959, from the verbal phrase, from iron (v.) + on (adv.).
ironside
name given to a man of great hardihood or bravery, c. 1300, first applied to Edmund II, king of England (d.1016), later also to Oliver Cromwell and his troops. Old Ironsides as a nickname of U.S.S. "Constitution" dates from that ship's defeat of H.M.S. "Guerriere" on Aug. 19, 1812, in the War of 1812.
ironstone (n.)
1520s, from iron (n.) + stone (n.). As a type of hard, white pottery, 1825.
ironwork (n.)
also iron-work, "objects made of iron," early 15c., from iron (n.) + work (n.). Related: Iron-worker (15c.). Iron works "iron foundry" is from 1580s.
Iroquois
1660s (adj.); 1670s (n.) "member of the confederated Indian tribes of central New York," from French (c. 1600); not an Iroquoian word, perhaps from an Algonquian language. Related: Iroquoian (1690s). Originally the Mohawks, Oneidas, Onodagas, Cayugas, and Senecas.
irradiance (n.)
1660s, from Latin irradiantem (nominative irradians), present participle of irradiare "to shine forth" (see irradiate). Related: Irradiancy (1640s).
irradiant (adj.)
1520s, from Latin irradiantem (nominative irradians), present participle of irradiare "to shine forth" (see irradiate). Related: Irradiantly.
irradiate (v.)
c. 1600, "to cast beams of light upon," from Latin irradiatus, past participle of irradiare "shine forth, beam upon, illumine," from assimilated form of in- "into, in" (from PIE root *en "in") + radiare "to shine" (see radiate (v.)). Meaning "expose to radiation other than light" (originally X-rays) is from 1901. Related: Irradiated; irradiating.
irradiation (n.)
1580s, in reference to light (literally and figuratively), from French irradiation, noun of action from past participle stem of Latin irradiare (see irradiate). Of X-rays, etc., from 1901.
irradicable (adj.)
"that cannot be rooted out," 1728, from assimilated form of in- (1) "not, opposite of" + radicable, from Latin radix "root" (from PIE root *wrād- "branch, root"). Latin radicare meant "to take root," and English irradicate (v.) means both "root out" (1709) and "to root, fix by the root" (1660s).
irrational (adj.)
late 15c., "not endowed with reason" (of beasts, etc.), from Latin irrationalis/inrationalis "without reason, not rational," from assimilated form of in- "not, opposite of" (see in- (1)) + rationalis "of or belonging to reason, reasonable" (see rational (adj.)).
Meaning "illogical, absurd" is attested from 1640s. Related: Irrationally. The mathematical sense "inexpressible in ordinary numbers" is from late 14c. in English, from use of the Latin word as a translation of Greek alogon in Euclid.
irrationality (n.)
1560s, originally in the mathematical sense, from irrational + -ity. Meaning "unreasonableness, absurdity" is from 1640s.
irreclaimable (adj.)
1660s, from assimilated form of in- (1) "not, opposite of" + reclaimable (see reclaim (v.)). Related: Irreclaimably; irreclaimability.
irrecognition (n.)
1820, from assimilated form of in- (1) "not, opposite of" + recognition.
irreconcilable (adj.)
1590s, from assimilated form of in- (1) "not, opposite of" + reconcilable, if that word is so old. Or perhaps from French irréconcilable (16c.). Related: Irreconcilably. As a noun, "one who refuses reconciliation or compromise" (especially in politics), from 1748.
irreconciliation (n.)
1640s, from ir- "not, opposite of" + reconciliation. Irreconcilement in the same sense is from 1737.
irrecoverable (adj.)
mid-15c., from Old French irrecovrable (Modern French irrecouvrable), from assimilated form of in- "not, opposite of" (see in- (1)) + recovrable (see recover). In same sense irrecuperable (from Late Latin irrecuperabilis) is from mid-14c. Related: Irrecoverably.
irredeemable (adj.)
c. 1600, from assimilated form of in- (1) "not, opposite of" + redeemable. Related: Irredeemably.
Irredentist (n.)
1882, member of Italian political party formed 1878 which demanded the annexation of neighboring regions where a part of the population was Italian-speaking (Trieste, South Tyrol, Nice, Corsica, etc.); from Italian Irredentista, from irredenta (Italia) "unredeemed (Italy)," fem. of irredento, from in- "not, opposite of" (see in- (1)) + redento, from Latin redemptus, past participle of redimere (see redemption). Related: Irredentism.
irreducible (adj.)
1530s, from assimilated form of in- (1) "not, opposite of" + reducible. Related: Irreducibly; irreducibility.
irrefragable (adj.)
"that cannot be refuted," literally "incapable of being broken down," 1530s, from French irréfragable (16c.) and directly from Late Latin irrefragabilis, from assimilated form of in- "not, opposite of" (see in- (1)) + Latin refragari "to oppose, contest," from re- "back" (see re-) + frag-, base of frangere "to break" (from PIE root *bhreg- "to break"). Related: irrefragably; irrefragability.
irrefrangible (adj.)
1722, "that cannot be broken or violated," from assimilated form of in- "not, opposite of" (see in- (1)) + refrangible. Related: Irrefrangibly.
irrefutable (adj.)
"incapable of being disproved," 1610s, from Late Latin irrefutabilis "irrefutable," from assimilated form of in- "not, opposite of" (see in- (1)) + refutabilis "refutable," from refutare (see refute). Related: Irrefutably; irrefutability.
irregardless (adj.)
an erroneous word that, etymologically, means the opposite of what it is used to express; probably a blend of irrespective and regardless, and perhaps inspired by the colloquial use of the double negative as an emphatic. Attested from at least 1870s (e.g. "Portsmouth Times," Portsmouth, Ohio, U.S.A., April 11, 1874: "We supported the six successful candidates for Council in the face of a strong opposition. We were led to do so because we believed every man of them would do his whole duty, irregardless of party, and the columns of this paper for one year has [sic] told what is needed.").
irregular (adj.)
late 14c., "not in conformity with Church rules," from Old French irreguler "irregular, incapable, incompetent" (13c., Modern French irrégulier), from Medieval Latin irregularis "not regular," from assimilated form of in- "not, opposite of" (see in- (1)) + Latin regularis "having rules" (see regular (adj.)). General sense of "not conforming to regular rules or principles" is from late 15c. "It expresses the fact of being out of conformity with rule, but implies nothing more with certainty. Yet the word is sometimes used in a sinister sense, as though it were a euphemism for something worse." [Century Dictionary] Meaning "unsymmetrical" is from 1580s. In reference to variable stars, from 1797.
irregularity (n.)
early 14c., "violation of Church rules governing admission to clerical office," from Old French irregularité (14c.) and directly from Medieval Latin irregularitas "irregularity," from irregularis "not regular" (see irregular (adj.)). Meaning "that which is irregular" is from late 15c.; sense of "state of non-conformity to rule" is from 1590s; meaning "want of symmetry" is from 1640s.
irregular (n.)
"one not belonging to a regular body" of any sort, "one not subject to or not conforming with established regulations," 1610s, from irregular (adj.). Main modern sense of "a soldier not of the regular army" is from 1747.
irrelevance (n.)
1735, from irrelevant + -ance. Earlier in the same sense was irrelevancy (1590s).
irrelevant (adj.)
1680s, from assimilated form of in- (1) "not, opposite of" + relevant. Related: Irrelevantly.
irreligious (adj.)
"not religious, without religious principles; condemning religion, impious, ungodly," c. 1400, from Late Latin irreligiosus "irreligious, impious," from assimilated form of in- "not, opposite of" (see in- (1)) + religiosus (see religious). Related: Irreligiously.
irreligion (n.)
"lack of religion, contempt of religion, impiety," 1590s, from French irréligion (16c.) or directly from Late Latin irreligionem (nominative irreligio) "irreligion, impiety," from assimiliated form of in- "not" (see in- (1)) + religio (see religion).
irremediably (adv.)
mid-15c., irremediabili, from irremediable + -ly (2).
irremediable (adj.)
"beyond remedy," mid-15c., from Late Latin irremediabilis "incurable," from assimilated form of in- "not, opposite of" (see in- (1)) + remediabilis "that may be healed, curable" (see remediable).
irremovable (adj.)
"not capable of or subject to removal," 1590s, from assimilated form of in- (1) "not, opposite of" + removable. Related: Irremovably; irremovability.
irreparable (adj.)
early 15c., from Old French irréparable (12c.), from Latin irreparabilis "not to be repaired or recovered," from assimilated form of in- "not, opposite of" (see in- (1)) + reparabilis "that can be repaired" (see repair (v.)). Irrepairable, from the English verb, was used 16c.-17c. but seldom was seen after.
irreparably (adv.)
mid-15c., from irreparable + -ly (2).
irreplaceable (adj.)
1806, from assimilated form of in- (1) "not, opposite of" + replaceable. Related: Irreplaceably.
irreprehensible (adj.)
"blameless," late 14c., from Late Latin irreprehensibilis, from Latin irreprehensus "blameless, without blame," from assimilated form of in- "not, opposite of" (see in- (1)) + reprehensibilis, from past participle stem of Latin reprehendere "to blame, censure, rebuke; seize, restrain" (see reprehend).
irrepressible (adj.)
"not able to be controlled or restrained," 1763, from assimilated form of in- (1) "not, opposite of" + repress (v.) + -ible.
Related: Irrepressibly. "Common Sense" (1777) has unrepressible.
irreproachable (adj.)
1630s, from French irréprochable (15c.), from assimilated form of in- "not, opposite of" (see in- (1)) + réprochable (see reproach (n.)). Related: Irreproachably.
irreption (n.)
"a creeping in," 1590s, from Late Latin irreptionem (nominative irreptio), noun of action from past participle stem of Latin irrepere, from assimilated form of in- "in" (from PIE root *en "in") + repere "to creep" (see reptile).
irreputable (adj.)
"disreputable," 1709, from assimilated form of in- (1) "not, opposite of" + reputable.
irresistible (adj.)
1590s, from Late Latin irresistibilis, from assimilated form of in- "not, opposite of" (see in- (1)) + resistere (see resist). Related: Irresistibly; irresistibility.
irresistance (n.)
1640s, from assimilated form of in- "not, opposite of" (see in- (1)) + resistance.
irresolute (adj.)
"not firm in purpose, wavering, given to doubt or hesitation," 1570s, from Latin irresolutus "not loosed, not loosened," from assimilated form of in- "not, opposite of" (see in- (1)) + resolutus (see resolute). Related: Irresolutely.
irresolution (n.)
1590s, from assimilated form of in- (1) "not, opposite of" + resolution. Perhaps from or based on French irrésolution (16c.).
irresolvable (adj.)
1650s, "insoluble," from assimilated form of in- (1) "not, opposite of" + resolvable. Meaning "that cannot be resolved into parts" is from 1785. Related: Irresolvably.
irrespective (adj.)
1620s (implied in irrespectively), "disrespectful," from assimilated form of in- (1) "not, opposite of" + respective in its sense of "regardful." Meaning "without taking account of particular circumstances or conditions" had developed by 1690s, from the notion of "not observing or noting with attention." In modern use it tends to be adverbial, in irrespective of, a use attested by c. 1800.
irresponsive (adj.)
"not responsive, not answering," 1797, from assimilated form of in- "not, opposite of" + responsive.
irresponsible (adj.)
1640s, "not legally answerable for conduct or actions," from assimilated form of in- (1) "not, opposite of" + responsible. Meaning "not acting with a sense of responsibility" is from 1680s. Related: Irresponsibly.
irresponsibility (n.)
1767; see irresponsible + -ity.
irretractable (adj.)
1744, from assimilated form of in- "not, opposite of" + retractable.
irretrievable (adj.)
"not recoverable," 1690s (implied in irretrievably), from assimilated form of in- (1) "not, opposite of" + retrievable. Related: Irretrievability.
irreverence (n.)
mid-14c., from Old French irreverence (13c.) or directly from Latin irreverentia "want of reverence, disrespect," from irreverentem (nominative irreverens) "disrespectful, irreverent," from assimilated form of in- "not, opposite of" (see in- (1)) + reverens, present participle of revereri "to stand in awe of" (see revere).