Online Etymology Dictionary

inhere (v.): 1580s, "to exist, have being," from Latin inhaerere "to stick in or to" (see inherent). Figurative (immaterial) use attested by 1610s (also in Latin). Related: Inhered; inhering.
inherence (n.): 1570s, from Medieval Latin inhaerentia, from inhaerentem (see inherent). Related: Inherency (c.1600).
inherent (adj.): 1570s, from Latin inhaerentem (nominative inhaerens), present participle of inhaerere "be closely connected with," literally "adhere to," from in- "in" (see in- (2)) + haerere "to stick" (see hesitation). Related: Inherently.
inherit (v.): c.1300, "to make (someone) an heir," from Old French enheriter "make heir, appoint as heir," from Late Latin inhereditare "to appoint as heir," from Latin in- "in" (see in- (2)) + hereditare "to inherit," from heres (genitive heredis) "heir" (see heredity). Sense of "receive inheritance" arose mid-14c.; original sense is retained in disinherit. Related: Inherited; inheriting.
inheritance (n.): late 14c., enheritaunce "fact of receiving by hereditary succession;" early 15c. as "that which is inherited," from Anglo-French enheritance, Old French enheritaunce, from enheriter (see inherit). Heritance "act of inheriting" is from mid-15c.
inhibit (v.): early 15c., "to forbid, prohibit," back-formation from inhibition or else from Latin inhibitus, past participle of inhibere "to hold in, hold back, keep back" (see inhibition). Psychological sense (1876) is from earlier, softened meaning of "restrain, check, hinder" (1530s). Related: Inhibited; inhibiting.
inhibition (n.): late 14c., "formal prohibition; interdiction of legal proceedings by authority;" also, the document setting forth such a prohibition, from Old French inibicion and directly from Latin inhibitionem (nominative inhibitio) "a restraining," from past participle stem of inhibere "to hold in, hold back, keep back," from in- "in, on" (see in- (2)) + habere "to hold" (see habit). Psychological sense of "involuntary check on an expression of an impulse" is from 1876.
inhibitor (n.): 1868 in scientific use (earlier as a Scottish legal term), agent noun in Latin form from inhibit.
inhibitory (adj.): late 15c., from Medieval Latin inhibitorius, from past participle stem of Latin inhibere (see inhibition).
inhospitable (adj.): 1560s, from Middle French inhospitable (15c.), from Medieval Latin inhospitabilis (equivalent of Latin inhospitalis), from in- "not" (see in- (1)) + Medieval Latin hospitabilis (see hospitable).
inhouse (adj.): also in-house, 1955, from in + house.
inhuman (adj.): mid-15c., "cruel," from Latin inhumanus "inhuman, savage, cruel, rude, barbarous," from in- "not, opposite of" (see in- (1)) + humanus "human" (see human). Spelled inhumane till 18c. (see humane).
inhumane (adj.): late 15c., from Latin inhumanus (see inhuman). Originally a variant spelling and pronunciation of inhuman, it appears to have died out 17c. but been revived c.1822 as a negative form of humane.
inhumanity (n.): late 15c., from French inhumanité (14c.) or directly from Latin inhumanitatem (nominative inhumanitas) "inhuman conduct, savageness," noun of quality from inhumanus (see inhuman).
And Man, whose heav'n-erected face
The smiles of love adorn,--
Man's inhumanity to man
Makes countless thousands mourn!
[Robert Burns, "Man was Made to Mourn," 1784]
inhumation (n.): 1630s, noun of action from Latin inhumare (see inhume).
inhume (v.): c.1600 (implied in inhumed), from Latin inhumare "to bury," literally "to put into the ground," from in- "in" (see in- (2)) + humus "earth, soil" (see humus).
Inigo: masc. proper name, from Spanish Iñigo, probably from Latin Ignatius.
inimical (adj.): 1640s, from Late Latin inimicalis "hostile," from Latin inimicus "unfriendly, an enemy" (see enemy).
inimitability (n.): 1711, from inimitable + -ity.
inimitable (adj.): late 15c., from Latin inimitabilis "that cannot be imitated," from in- "not, opposite of" (see in- (1)) + imitabilis (see imitable). Related: Inimitably.
iniquitous (adj.): 1726, from iniquity + -ous. Related: Iniquitously.
iniquity (n.): c.1300, "hostility, malevolence; a hostile action," from Old French iniquité "wickedness, unfavorable situation," from Latin iniquitatem (nominative iniquitas) "unequalness, unevenness, injustice," noun of quality from iniquus "unjust, unequal; slanting, steep," from in- "not" (see in- (1)) + aequus "just, equal" (see equal). For vowel change, see acquisition. Meaning "evil, wickedness" is from late 14c.
initial (adj.): 1520s, "of or pertaining to a beginning," from Middle French initial or directly from Latin initialis "initial, incipient," from initium "a beginning, an entrance," from past participle stem of inire "to go into, enter upon, begin," from in- "into, in" (see in- (2)) + ire "to go" (see ion).
initial (n.): "initial letter of a name or surname," 1620s, from initial (adj.) in a specialized sense "standing at the beginning of a word, sentence, etc."
initial (v.): "to mark or sign with initials," 1864, American English, from initial (n.). Related: Initialed; initialing.
initialism (n.): word formed from the first letters of other words or a phrase, 1957, from initial (n.) + -ism. The distinction from acronym is not universally agreed-upon; in general, words such as NATO, where the letters form a word, are regarded as acronyms, those such as FBI, where the letters sound as letters, are initialisms.
initialize (v.): 1833, "to designate by initials," from initial + -ize. Meaning "to make ready for operation" is from 1957. Related: Initialized; initializing.
initiate (n.): "one who has been initiated," 1811, from past participle adjective initiate (c.1600); see initiate (v.).
initiate (v.): c.1600, "introduce to some practice or system," also "begin, set going," from Latin initiatus, past participle of initiare "to begin, originate," from initium "beginning" (see initial). In some senses a back-formation from initiation. Related: Initiated; initiates; initiating; initiator.
initiation (n.): 1580s, from Middle French initiation or directly from Latin initiationem (nominative initiatio) "participation in secret rites," noun of action from past participle stem of initiare "originate, initiate," from initium (see initial).
initiative (n.): 1793, "that which begins," also "power of initiating," from French initiative (1560s), from Latin initiatus (see initiation). First attested in English in writings of William Godwin. Phrase take the initiative recorded by 1844.
initiatory (adj.): 1610s, from Latin initiat-, stem of initiare (see initiate (v.)) + -ory.
inject (v.): c.1600, from Latin iniectus "a casting on, throwing over," past participle of inicere "to throw in or on," from in- "in" (see in- (2)) + -icere, comb. form of iacere "to throw" (see jet (v.)). Related: Injectable; injected; injecting.
injection (n.): "forcing a fluid into a body" (with a syringe, etc.), early 15c., from Middle French iniection (14c.) or directly from Latin iniectionem (nominative iniectio), noun of action from past participle stem of inicere (see inject).
injudicious (adj.): 1640s, from in- (1) "not, opposite of" + judicious. Related: Injudiciously.
Injun (n.): 1812 (from 1683 as Ingin), spelling representing American English colloquial pronunciation of Indian (q.v.). Honest Injun as an asseveration of truthfuless first recorded 1868, from the notion of assurance extracted from Indians of their lack of duplicity.
"Honest Injun?" inquired Mr. Wilder, using a Western phrase equivalent to demanding of the narrator of a story whether he is strictly adhering to the truth. ["The Genial Showman," London, 1870]
The term honest Indian is attested from 1676.
injunction (n.): early 15c., from Late Latin injunctionem (nominative injunctio) "a command," noun of action from past participle stem of Latin injungere "impose," literally "attach to" (see enjoin).
injunctive: 1620s, from Latin injunct-, past participle stem of injungere (see enjoin) + -ive. As a term in grammar, from 1910.
injure (v.): mid-15c., "do an injustice to, dishonor," probably a back-formation from injury, or else from Middle French injuriier, from Latin injurare. Injury also served as a verb (late 15c.). Related: Injured; injuring.
injurious (adj.): early 15c., "abusive," from Middle French injurios (14c., Modern French injurieux) and directly from Latin injuriosus "unlawful, wrongful, harmful, noxious," from injuria (see injury). Related: Injuriously.
injury (n.): late 14c., "harm, damage, loss; a specific injury," from Anglo-French injurie "wrongful action," from Latin injuria "wrong, hurt, injustice, insult," noun use of fem. of injurius "wrongful, unjust," from in- "not, opposite of" (see in- (1)) + ius (genitive iuris) "right, law" (see jurist).
injustice (n.): late 14c., from Old French injustice, from Latin injustitia "injustice," from injustus "unjust, wrongful, oppressive," from in- "not" (see in- (1)) + justus "just" (see just (adj.)).
ink (n.): "the black liquor with which men write" [Johnson], mid-13c., from Old French enque "dark writing fluid" (11c.), from Late Latin encaustum, from Greek enkauston "purple or red ink," used by the Roman emperors to sign documents, originally a neuter adjective form of enkaustos "burned in," from stem of enkaiein "to burn in," from en- "in" + kaiein "to burn" (see caustic). The word is from a Greek method of applying colored wax and fixing it with heat. The Old English word for it was simply blæc, literally "black." Ink-blot test attested from 1928.
ink (v.): "to mark or stain in ink," 1560s, from ink (n.). Meaning "to cover (a printing plate, etc.) with ink" is from 1727. Related: Inked; inking.
inkhorn (n.): late 14c., "small portable vessel (originally made of horn) for holding ink," from ink (n.) + horn (n.). Used attributively as an adjective for things (especially vocabulary) supposed to be beloved by scribblers and bookworms (1540s). An Old English word for the thing was blæchorn.
inkling (n.): c.1400, apparently from the gerund of Middle English verb inclen "utter in an undertone, hint at, hint" (mid-14c.), which is of unknown origin; perhaps related to Old English inca "doubt, suspicion."
inky (adj.): "as black as ink," 1590s, from ink (n.) + -y (2). Related: Inkily; inkiness.
inlaid (adj.): 1590s, from in + laid, past participle of lay (v.).
inland (adj.): Old English inn lond "land around the mansion of an estate," from in + land (n.). Meaning "interior parts of a country, remote from the sea or borders" is from 1570s. As an adjective, "of or pertaining to interior parts of a country," from 1550s.
inlandish (adj.): 1650s, "produced at home, domestic, native," from inland + -ish. Also "characteristic of inland regions" (1849).