ineducable (adj.) Look up ineducable at
"not capable of being instructed," 1858, from in- (1) "not" + educable. Related: Ineducably; ineducability (1871).
ineffability (n.) Look up ineffability at
"unspeakableness," 1620s, from ineffable + -ity.
ineffable (adj.) Look up ineffable at
late 14c., "beyond expression, too great for words, inexpressible," from Old French ineffable (14c.) or directly from Latin ineffabilis "unutterable," from in- "not, opposite of" (see in- (1)) + effabilis "speakable," from effari "utter," from ex- "out" (see ex-) + fari "to say, speak," from PIE root *bha- (2) "to speak, tell, say" (see fame (n.)). Meaning "that may not be spoken" is from 1590s. Plural noun ineffables was, for a time, a jocular euphemism for "trousers" (1823; see indescribable). Related: Ineffably.
ineffaceable (adj.) Look up ineffaceable at
1804, from in- "not, opposite of" (see in- (1)) + effaceable (see efface). Perhaps modeled on French ineffaçable (16c.).
ineffectible (adj.) Look up ineffectible at
"that cannot be carried out, impracticable," 1803, from in- (1) "not, opposite of" + effectible (see effect (v.)).
ineffective (adj.) Look up ineffective at
1650s, from in- (1) "not, opposite of" + effective. Related: Ineffectively; ineffectiveness (1744).
ineffectual (adj.) Look up ineffectual at
early 15c., from in- (1) "not, opposite of" + effectual. Related: Ineffectually; ineffectuality.
inefficacious (adj.) Look up inefficacious at
"not producing the desired effect," 1650s, from in- (1) "not, opposite of" + efficacious. Related: Inefficaciously; inefficaciousness (1640s).
inefficacy (n.) Look up inefficacy at
"want of force or virtue to produce the desired effect," 1610s, from Late Latin inefficacia, from inefficacem (nominative inefficax), from in- "not, opposite of" (see in- (1)) + Latin efficax "powerful, effectual, efficient" (see efficacy).
inefficiency (n.) Look up inefficiency at
1749; see in- (1) "not, opposite of" + efficiency (n.).
inefficient (adj.) Look up inefficient at
1748, "not producing or incapable of producing the desired effect," from in- (1) "not, opposite of" + efficient. Related: Inefficiently.
inelastic (adj.) Look up inelastic at
1748, "not rebounding after a strain," from in- (1) "not, opposite of" + elastic (adj.). Figurative sense "rigid, unyielding" attested by 1867. Related: Inelasticity.
inelegance (n.) Look up inelegance at
1690s, from French inélégance (16c.) or directly from Late Latin inelegantia, from in- "not, opposite of" (see in- (1)) + Latin elegantia "taste, propriety, refinement" (see elegance).
inelegant (adj.) Look up inelegant at
c. 1500, from Middle French inélégant (15c.), from Latin inelegantem (nominative inelegans) "not elegant, not choice," also "without taste, without judgment," from in- "not" (see in- (1)) + elegans (see elegant). Related: Inelegantly.
ineligible (adj.) Look up ineligible at
1763, from in- (1) "not, opposite of" + eligible. Perhaps modeled on French inéligible. Related: Ineligibility.
ineluctable (adj.) Look up ineluctable at
"not to be escaped by struggling," 1620s, from French inéluctable (15c.) or directly from Latin ineluctabilis "unavoidable, inevitable," from in- "not, opposite of" (see in- (1)) + eluctabilis "that may be escaped from," from eluctari "to struggle out of," from ex- "out" (see ex-) + luctari "to struggle" (see reluctance).
inenarrable (adj.) Look up inenarrable at
"inexpressible, that cannot be told, indescribable," c. 1500, from Old French inenarrable (14c.) or directly from Latin inenarrabilis, from in- "not, opposite of" (see in- (1)) + enarrabilis "describable," from enarre "to narrate."
inept (adj.) Look up inept at
c. 1600, "not fit or suitable, inapt," also "absurd, foolish," from French inepte "incapable" (14c.) or directly from Latin ineptus "unsuitable, improper, impertinent; absurd, awkward, silly, tactless," from in- "not, opposite of" (see in- (1)) + aptus "apt" (see apt). Related: Ineptly; ineptness.
ineptitude (n.) Look up ineptitude at
1610s, from French ineptitude, from Latin ineptitudo, noun of quality from ineptus "unsuitable, absurd" (see inept).
inequable (adj.) Look up inequable at
"not uniform, changeable," 1716, from Latin inaequabilis "unequal," from in- "not" (see in- (1)) + aequabilis "similar, equal; constant, not varying" (see equable). Related: Inequability (1580s).
inequal (adj.) Look up inequal at
late 14c., from Old French inequal (14c.), from Latin inaequalis "unequal," from in- "not, opposite of" (see in- (1)) + aequalis "equal" (see equal).
inequality (n.) Look up inequality at
early 15c., "difference of rank or dignity," from Old French inequalité (14c., Modern French inégalité) and directly from Medieval Latin inaequalitas, from Latin inaequalis "unequal, unlike, different (in size); changeable, inconstant," from in- "not, opposite of" (see in- (1)) + aequalis "equal" (see equal). In reference to magnitude, number, intensity, etc., from 1530s.
inequitable (adj.) Look up inequitable at
"unfair, unjust," 1660s, from in- (1) "not, opposite of" + equitable, which is ultimately from Latin aequus "even, just, equal." Related: Inequitably. The same formation in English has also meant "impassable on horses, unfit for riding over" (1620s), from Latin inequabilis, from equus "a horse" (see equine).
inequity (n.) Look up inequity at
"unfairness," 1550s, from in- (1) "not, opposite of" + equity. Formed from the same elements as iniquity, but done in English. Related: Inequities.
ineradicable (adj.) Look up ineradicable at
1794, from in- (1) "not, opposite of" + eradicable (see eradicate). Related: Ineradicably.
inerrable (adj.) Look up inerrable at
"incapable of erring," 1610s, from Late Latin inerrabilis "unerring," from in- "not, opposite of" (see in- (1)) + errabilis, from Latin errare "to wander; to err" (see err). Related: Inerrability "infallibility" (1620s).
inerrancy (n.) Look up inerrancy at
1788, from inerrant + -cy.
inerrant (adj.) Look up inerrant at
1650s, in reference to "fixed" stars (as opposed to "wandering" planets), from Latin inerrantem (nominative inerrans) "not wandering, fixed (of stars)," from in- "not, opposite of" (see in- (1)) + errans, present participle of errare "to wander, stray, roam, rove" (see err). Meaning "unerring, free from error" is from 1785.
inert (adj.) Look up inert at
1640s, "without inherent force, having no power to act or respond," from French inerte (16c.) or directly from Latin inertem (nominative iners) "unskilled, incompetent; inactive, helpless, weak, sluggish; worthless," used of stagnant fluids, uncultivated pastures, expressionless eyes. It is a compound of in- "without, not, opposite of" (see in- (1)) + ars (genitive artis) "skill" (see art (n.)). In chemistry, "having no active properties, neutral" (1800), specifically from 1885 of certain chemically inactive, colorless, odorless gases. Of persons or creatures, "indisposed or unable to move or act," from 1774.
inertia (n.) Look up inertia at
1713, "that property of matter by virtue of which it retains its state of rest or of uniform rectilinear motion so long as no foreign cause changes that state" [Century Dictionary], introduced as a term in physics 17c. by German astronomer and physician Johann Kepler (1571-1630) as a special sense of Latin inertia "unskillfulness, ignorance; inactivity, idleness," from iners (genitive inertis) "unskilled; inactive" (see inert). Also sometimes vis inertia "force of inertia." Used in 1687 by Newton, writing in Modern Latin. The classical Latin sense of "apathy, passiveness, inactivity" is attested in English from 1822.
inertial (adj.) Look up inertial at
"pertaining to inertia," 1737, from inertia + -al (1). Related: Inertially.
inertness (n.) Look up inertness at
"inactivity; fact of being inert," 1660s, from inert + -ness.
inescapable (adj.) Look up inescapable at
1792, from in- (1) "not, opposite of" + escapable (see escape (v.)). Related: Inescapably.
inestimable (adj.) Look up inestimable at
late 14c., "beyond estimation or measure, not to be computed," from Old French inestimable "priceless" (14c.) or directly from Latin inaestimabilis "invaluable, incalculable," also "not estimable, valueless," from in- "not, opposite of" (see in- (1)) + aestimabilis "valuable, estimable," from aestimare (see esteem (v.)). Meaning "too precious to set a value on, priceless" is attested by 1570s. Related: Inestimably; inestimability.
inevitability (n.) Look up inevitability at
1640s, from inevitable + -ity. Perhaps modeled on French inévitabilité.
inevitable (adj.) Look up inevitable at
"unavoidable," mid-15c., from Latin inevitabilis "unavoidable," from in- "not, opposite of" (see in- (1)) + evitabilis "avoidable," from evitare "to avoid," from ex- "out" (see ex-) + vitare "shun," originally "go out of the way." As a noun from 1850. Related: Inevitableness.
inevitably (adv.) Look up inevitably at
mid-15c., from inevitable + -ly (2).
inexact (adj.) Look up inexact at
1791, from in- (1) "not, opposite of" + exact (adj.). Perhaps modeled on French inexact (18c.). Related: Inexactly.
inexactitude (n.) Look up inexactitude at
1786, from in- (1) "not, opposite of" + exactitude. Perhaps modeled on French inexactitude (18c.).
inexcusable (adj.) Look up inexcusable at
early 15c., from Latin inexcusabilis "without excuse; affording no excuse," from in- "not, opposite of" (see in- (1)) + excusabilis, from excusare "apologize, make an excuse for" (see excuse (v.)). Related: Inexcusably.
inexhaustible (adj.) Look up inexhaustible at
c. 1600, from in- (1) "not, opposite of" + exhaustible (see exhaust (v.)). Perhaps modeled on French inexhaustible (15c.). Related: Inexhaustibly.
inexorable (adj.) Look up inexorable at
"unyielding, unrelenting," 1550s, from Middle French inexorable and directly from Latin inexorabilis "that cannot be moved by entreaty, unyielding," from in- "not, opposite of" (see in- (1)) + exorabilis "able to be entreated," from exorare "to prevail upon," from ex- "out" (see ex-) + orare "pray" (see orator). Related: Inexorably; inexorability.
inexpediency (n.) Look up inexpediency at
1640s; see inexpedient + -cy.
inexpedient (adj.) Look up inexpedient at
"not suitable to the purpose or circumstances," c. 1600, from in- (1) "not, opposite of" + expedient. Related: Inexpedience; inexpediently.
inexpensive (adj.) Look up inexpensive at
1670s, from in- (1) "not, opposite of" + expensive. Related: Inexpensively.
inexperience (n.) Look up inexperience at
1590s, from French inexpérience (15c.) or directly from Late Latin inexperientia "inexperience," from in- "not, opposite of" (see in- (1)) + Latin experientia "experimental knowledge; experiment; effort" (see experience (n.)).
inexperienced (adj.) Look up inexperienced at
"lacking the knowledge or skill gained by experience," 1620s, past-participle adjective from inexperience.
inexpert (adj.) Look up inexpert at
mid-15c., from in- (1) "not, opposite of" + expert (adj.), or else from Old French inexpert or directly from Latin inexpertus "without experience, unpracticed; untried, untested." Related: Inexpertly.
inexpiable (adj.) Look up inexpiable at
1560s, from Latin inexpiabilis "that cannot be atoned for," from in- "not" (see in- (1)) + expiabilis, from expiare "make amends for, purify, purge by sacrifice" (see expiation). The Inexpiable War was between Carthage and its Libyan mercenaries after the end of the First Punic War (241 B.C.E.). Related: Inexpiably.
inexplicable (adj.) Look up inexplicable at
early 15c., from Middle French inexplicable or directly from Latin inexplicabilis "that cannot be unfolded or disentangled, very intricate," figuratively, "inexplicable," from in- "not, opposite of" (see in- (1)) + explicabilis "that may be explained" (see explicable).

As a noun, 1745, "something that cannot be explained;" jocular inexplicables "trousers" is from 1829. Related: Inexplicably; inexplicability.