increase (n.) Look up increase at
late 14c., "action of increasing; results of an increasing," from increase (v.) or from verbs formed from the noun in Old French or Anglo-French. The stress shifted from 18c. to distinguish it from the verb.
increasingly (adv.) Look up increasingly at
late 14c., from increasing (see increase (v.)) + -ly (2).
incredible (adj.) Look up incredible at
early 15c., "unbelievable, surpassing belief as to what is possible," from Latin incredibilis "not to be believed, extraordinary," from in- "not" (see in- (1)) + credibilis "worthy of belief" (see credible). Used c. 1400 in a now-extinct sense of "unbelieving, incredulous." Related: Incredibly; incredibility.
incredulity (n.) Look up incredulity at
"disbelieving frame of mind," early 15c., from Middle French incrédulité, from Latin incredulitatem (nominative incredulitas) "unbelief," noun of quality from incredulus "unbelieving" (see incredulous).
incredulous (adj.) Look up incredulous at
"unbelieving," 1570s, from Latin incredulus "unbelieving, incredulous," from in- "not" (see in- (1)) + credulus (see credulous). Formerly also of religious beliefs. Related: Incredulously; incredulousness.
increment (n.) Look up increment at
mid-15c., "act or process of increasing," from Latin incrementum "growth, increase; an addition," from stem of increscere "to grow in or upon" (see increase (v.)). Meaning "amount of increase" first attested 1630s.
incremental (adj.) Look up incremental at
1715, from increment + -al (1). Related: Incrementally.
increpation (n.) Look up increpation at
"a chiding, a rebuking, censure," c. 1500, from Late Latin increpationem (nominative increpatio), noun of action from past participle stem of Latin increpare "to make noise at, scold, nag, upbraid," from in- "in" (see in- (2)) + crepare "to creak" (see raven (n.)).
incriminate (v.) Look up incriminate at
1730, back-formation from incrimination (q.v.) or else from Medieval Latin incriminatus, past participle of incriminare "to incriminate, accuse." Related: Incriminated; incriminating.
incrimination (n.) Look up incrimination at
1650s, noun of action from Medieval Latin incriminare "to incriminate, accuse," from in- "in" (see in- (2)) + criminare "to accuse of a crime," from crimen (genitive criminis) "crime" (see crime).
incroyable (n.) Look up incroyable at
1796, from French incroyable, literally "incredible" (15c.), from in- "not, opposite of, without" (see in- (1)) + croire "to believe," from Latin credere (see credo). A name for the French fop or dandy of the period of the Directory (1795-99). Said to be so called from their extravagant dress, and also, according to OED, from a favorite expression among them ("C'est vraiment incroyable").
incrustation (n.) Look up incrustation at
in early use also also encrustation, 1640s, from French encrustation, incrustation, from encruster (see encrust). Or perhaps from the obsolete English verb incrustate, which is attested from 1560s.
incubate (v.) Look up incubate at
1640s (transitive), "to brood upon, watch jealously" (figurative); 1721 in literal sense "to sit on (eggs) to hatch them," from Latin incubatus, past participle of incubare "to lie in or upon," also in the figurative sense "brood" (see incubation). Intransitive sense "to sit upon eggs" is from 1755. Related: Incubated; incubating.
incubation (n.) Look up incubation at
1610s, "a brooding," from Latin incubationem (nominative incubatio) "a laying upon eggs," noun of action from past participle stem of incubare "to hatch," literally "to lie on, rest on," from in- "on" (see in- (2)) + cubare "to lie" (see cubicle). The literal sense of "sitting on eggs to hatch them" in English is first recorded 1640s.
incubator (n.) Look up incubator at
"apparatus for hatching eggs by artificial heat," 1845, agent noun from incubate (v.). Late Latin incubator meant "one who lies in a place."
incubus (n.) Look up incubus at
"imaginary being or demon, credited with causing nightmares, and, in male form, consorting with women in their sleep," c. 1200, from Late Latin incubus (Augustine), from Latin incubo "nightmare, one who lies down on (the sleeper)," from incubare "to lie upon" (see incubate). Plural is incubi. Compare succubus.
inculcate (v.) Look up inculcate at
1540s, from Latin inculcatus, past participle of inculcare "force upon, insist; stamp in, impress, tread down," from in- "in" (see in- (2)) + calcare "to tread, press in," from calx (1) "heel" (see calcaneous). Related: Inculcated; inculcating.
inculcation (n.) Look up inculcation at
1550s, from inculcate (v.), or else Late Latin inculcationem (nominative inculcatio), noun of action from past participle stem of inculcare "to force upon; stamp in."
inculpable (adj.) Look up inculpable at
late 15c., from Late Latin inculpabilis "unblamable," from in- "not, opposite of" (see in- (1)) + culpabilis (see culpable).
inculpate (v.) Look up inculpate at
1799, "to accuse, bring charges against," from Medieval Latin inculpatus, past participle of inculpare "to reproach, blame, censure," from Latin in- "in" (see in- (2)) + culpare "to blame," from culpa "fault." But inculpable (late 15c.) means "not culpable, free from blame," from Latin in- "not" (see in- (1)) + culpare.
inculpation (n.) Look up inculpation at
"incrimination," 1798, noun of action from inculpate (v.). Perhaps from or modeled on French inculpation (18c.).
incumbency (n.) Look up incumbency at
"state of being an incumbent," c. 1600, from incumbent + -cy.
incumbent (n.) Look up incumbent at
early 15c., "person holding a church position," from Medieval Latin incumbentem (nominative incumbens) "holder of a church position," noun use of present participle of incumbere "to obtain or possess," from Latin incumbere "recline on," figuratively "apply oneself to," from in- "on" (see in- (2)) + -cumbere "lie down," related to cubare "to lie" (see cubicle). Extended to holders of any office from 1670s.
incumbent (adj.) Look up incumbent at
1560s, in relation to duties or obligations, from Medieval Latin incumbentem (nominative incumbens), present participle of incumbere (see incumbent (n.)). The literal, physical sense "lying or resting on something" is rare in English and first attested 1620s.
incumbrance (n.) Look up incumbrance at
see encumbrance.
incunabula (n.) Look up incunabula at
"swaddling clothes," also, figuratively, "childhood, beginnings, place where a thing had its earliest development," 1824, from Latin incunabula (neuter plural) "a cradle; a birthplace," figuratively "rudiments or beginnings," from in- "in" (see in- (2)) + cunabula, diminutive of cunae "cradle," from PIE *koi-na-, from root *kei- "to lie; bed, couch" (see cemetery).
incunabulum (n.) Look up incunabulum at
1861, singular of Latin incunabula "cradle, birthplace; rudiments or beginnings" (see incunabula); taken up (originally in German) as a word for any book printed late 15c., in the infancy of the printer's art.
incur (v.) Look up incur at
c. 1400, "bring (an undesirable consequence) upon oneself;" mid-15c. as "become liable for (payment or expenses)," from Anglo-French encurir, Old French encorir "to run, flee; commit, contract, incur" (Modern French encourir), from Latin incurrere "run into or against, rush at, make an attack;" figuratively, "to befall, happen, occur to," from in- "upon" (see in- (2)) + currere "to run" (see current (adj.)). Related: Incurred; incurring.
incurable (adj.) Look up incurable at
mid-14c., from Old French incurable "not curable" (13c.), from Late Latin incurabilis "not curable," from in- "not" (see in- (1)) + curabilis "curable" (see curable). As a noun, "incurable person," from 1650s. Related: Incurably.
incurious (adj.) Look up incurious at
1560s, "negligent, heedless," from Latin incuriosus "careless, negligent, unconcerned," from in- "not, opposite of, without" (see in- (1)) + curiosus (see curious). Meaning "uninquisitive" is from 1610s. Objective sense of "unworthy of attention" is from 1747. Related: Incuriously. Incuriosity is attested from c. 1600.
incursion (n.) Look up incursion at
"hostile attack," early 15c., from Old French incursion "invasion, attack, assault" (14c.) or directly from Latin incursionem (nominative incursio) "a running against, hostile attack," noun of action from past participle stem of incurrere "run into or against, rush at" (see incur).
incus (n.) Look up incus at
middle ear bone, 1660s, from Latin incus "anvil," from incudere "to forge with a hammer," from in- "in" + cudere "to strike, beat," from PIE *kau-do-, suffixed form of root *kau- "to hew, strike" (see hew). The bone so called by Belgian anatomist Andreas Vesalius (1514-1564).
indear (v.) Look up indear at
see endear.
indearing (adj.) Look up indearing at
see endearing.
indebted (adj.) Look up indebted at
late 14c., endetted "owing money, liable for borrowed money," past participle of endetten "to indebt, oblige," from Old French endeter "to involve in debt, run into debt," from en- "in" (see in- (2)) + dete "debt" (see debt). Figurative sense of "under obligation for favors or services" first attested 1560s. Spelling re-Latinized in English from 16c. The verb indebt is now rare or obsolete. Related: Indebtedness. Latin indebitus meant "not owed, not due."
indecency (n.) Look up indecency at
1580s, "outrageous conduct," from Latin indecentia "unseemliness, impropriety," noun of quality from indecentem "unbecoming" (see indecent). Now especially of conduct which violates recognized standards of propriety (1690s).
indecent (adj.) Look up indecent at
1560s, "unbecoming, in bad taste," from French indécent (14c.) or directly from Latin indecentem (nominative indecens) "unbecoming, unseemly," from in- "not, opposite of, without" (see in- (1)) + decens (see decent). Sense of "offending against propriety" is from 1610s. Indecent assault (1861) originally covered sexual assaults other than rape or intended rape, but by 1934 it was being used as a euphemism for "rape." Related: Indecently
indecipherable (adj.) Look up indecipherable at
1802, from in- (1) "not" + decipherable (see decipher (v.)). Undecipherable is older. Related: Indecipherably; indecipherability.
indecision (n.) Look up indecision at
1735, from in- (1) "not, opposite of, without" + decision. Perhaps from or modeled on French indécision (17c.), which Cotgrave's "French and English Dictionary" (1673) translates with An undecision.
indecisive (adj.) Look up indecisive at
1726, "inconclusive," from in- (1) "not, opposite of" + decisive. Meaning "vacillating, characterized by indecision" is from 1787. Related: Indecisively; indecisiveness.
indeclinable (adj.) Look up indeclinable at
late 14c., originally in grammar, from French indéclinable or directly from Latin indeclinabilis "unchangeable," also in grammar, from indeclinatus "unchanged, constant," from in- "not, opposite of" (see in- (1)) + declinatus, from declinare "to lower; avoid, deviate; bend from, inflect" (see decline (v.)). Related: Indeclinably.
indecorous (adj.) Look up indecorous at
1680s, "in bad taste," from Latin indecorus "unbecoming, unseemly, unsightly; disgraceful," from in- "not, opposite of, without" (see in- (1)) + decorus "becoming, fitting, seemly, proper" (see decorous). Related: Indecorously; indecorousness (1670s).
indecorum (n.) Look up indecorum at
1570s, from Latin indecorum, noun use of neuter of adjective indecorus "unbecoming, unseemly, unsightly" (see indecorous).
indeed (adv.) Look up indeed at
c. 1600, a contraction into one word of the prepositional phrase in dede "in fact, in truth" (early 14c.), from Old English dæd "a doing, act, action, event" (see deed (n.)). As an interjection, 1590s; as an expression of surprise or disgust, 1834. Emphatic form yes (or no) indeedy attested from 1856, American English.
indefatigability (n.) Look up indefatigability at
1630s, from indefatigable + -ity. Indefatigableness is from 1650s; indefatigation from 1640s.
indefatigable (adj.) Look up indefatigable at
1580s (implied in indefatigably), from French indefatigable (15c.), from Latin indefatigabilis "that cannot be wearied," from in- "not" (see in- (1)) + defatigare "to tire out," from de- "utterly, down, away" (see de-) + fatigare "to weary" (see fatigue (n.)).

Blount's "Glossographia" (1656) has defatigable, which also was in use elsewhere in 17c., but the modern use of defatigable (1948) probably is a jocular back-formation from indefatigable.
indefeasible (adj.) Look up indefeasible at
"not to be set aside or overcome," 1530s (implied in indefeasibly), from in- (1) "not, opposite of" + defeasible (see defeasance).
indefensible (adj.) Look up indefensible at
1520s, "that cannot be maintained or justified by argument," from in- (1) "not, opposite of" + defensible. From 1560s as "that cannot be maintained by force." Related: Indefensibly.
indefinability (n.) Look up indefinability at
1814, from indefinable + -ity.
indefinable (adj.) Look up indefinable at
"incapable of being exactly described," 1721, from in- (1) "not, opposite of" + definable (see define). Related: Indefinably.