Online Etymology Dictionary

Indic (adj.): "pertaining to India or its inhabitants," 1877, from Latin Indicus "of India," or Greek Indikos "of India;" see India. Especially in reference to the Indo-European languages of India, living and dead.
indicate (v.): 1650s, "to point out," back-formation from indication (q.v.) or else from Latin indicatus, past participle of indicare "to point out, show, indicate." Especially "to give suggestion of, be reason for inferring" (1706). Related: Indicated; indicating.
indication (n.): early 15c., "a sign, that which indicates," from Latin indicationem (nominative indicatio) "an indicating; valuation," noun of action from past participle stem of indicare "point out, show," from in- "into, in, on, upon" (see in- (2)) + dicare "proclaim" (see diction).
indicative (adj.): mid-15c., "that points out, states, or declares" (grammatical), from Old French indicatif (14c.), from Late Latin indicativus "serving to point out," from indicat-, past participle stem of Latin indicare "to point out, show" (see indication). The "mood in the conjugation of a Latin verb whose essential function is to state a fact (as opposed to a wish, supposition or command)" [Middle English Dictionary]. Related: Indicatively.
indicator (n.): 1660s, "that which indicates or points out," from Late Latin indicator, agent noun from indicare "to point out, show" (see indication). As a finger muscle, from 1690s. As a steam-cylinder's pressure gauge, 1839. As a device on a motor vehicle to signal intention to change direction, 1932.
indices (n.): according to OED, the plural form of index preferable in scientific and mathematical senses of that word.
indicia (n.): "indications, discriminating marks," Latin plural of indicium "a notice, information, disclosure, discovery," from index (genitive indicis); see index (n.).
indict (v.): formerly also endict, c. 1300, enditen, inditen, "bring formal charges against (someone); accuse of a crime," from Anglo-French enditer "accuse, indict, find chargeable with a criminal offense" (late 13c.), Old French enditier, enditer "to dictate, write, compose; (legally) indict," from Vulgar Latin *indictare "to declare, accuse, proclaim in writing," from in- "in" (see in- (2)) + Latin dictare "to say, compose in words" (see dictate (v.)).

Later 14c. non-legal senses "write, compose (a poem, etc.); dictate" have gone with the older form, endite (q.v.). Retained its French pronunciation after the spelling was re-Latinized c. 1600. The sense is perhaps partly confused with Latin indicare "to point out." In classical Latin, indictus meant "not said, unsaid" (from in- "not"). Related: Indictable; indicted; indicting.
indictable (adj.): mid-15c., enditable, "capable of being indicted, liable to indictment," from indict + -able. From 1721 of actions, "that may be punished by indictment."
indiction (n.): late 14c., "period of fifteen years," a chronological unit of the Roman calendar that continued in use through the Middle Ages, from Latin indictionem (nominative indictio), literally "declaration, appointment," noun of action from past participle stem of indicere "to declare publicly, proclaim, announce," from in- "in" (see in- (2)) + dicere "to speak, say, tell" (see diction).

Fixed by Constantine and reckoned from Sept. 1, 312. Originally for taxation purposes, it was "a common and convenient means for dating ordinary transactions" [Century Dictionary]. The name refers to the "proclamation," at the beginning of each period, of the valuation upon which real property would be taxed.
indictive (adj.): "proclaimed," 1650s, from Late Latin indictivus "proclaimed," from Latin indicere "to declare publicly, proclaim, announce," from in- "in" (see in- (2)) + dicere "to speak, say, tell" (see diction).
indictment (n.): formerly also endictment, c. 1300, endytement "action of accusing," from Anglo-French and Old French enditement, from enditer "accuse, indict" (see indict). Meaning "formal legal document containing a charge proved before a grand jury" is from c. 1500. Latin spelling restored 17c.
indie (n.): "independent record company," 1945, shortening of independent. Among the earliest mentioned were Continental, Majestic, and Signature. Used of film production companies since 1920s, of theaters from 1942; extended by 1984 to a type of pop music issued by such labels.
Indies: "India and adjacent regions and islands," 1550s, plural of Indie, Indy, from Middle English Ynde (early 13c.), the usual word in Middle English for "India," from the Old French form of Latin India (see India). Commonly applied to Asia and the East generally; later in a time of geographical confusion, it was applied to the Caribbean basin, which was distinguished from Asia proper by being called the West Indies.
indifference (n.): mid-15c., "quality of being neither good nor bad, neutral quality," from Latin indifferentia "want of difference, similarity," noun of quality from indifferentem (see indifferent). From late 15c. as "lack of prejudice, impartiality;" from 1650s as "state of being apathetic." Meaning "comparative mediocrity, inexcellence"" is from 1864.
indifferent (adj.): late 14c., "unbiased, impartial, not preferring one to the other" (of persons), "alike, equal" (of things), from Old French indifferent "impartial" or directly from Latin indifferentem (nominative indifferens) "not differing, not particular, of no consequence, neither good nor evil," from in- "not, opposite of" (see in- (1)) + differens, present participle of differre "set apart" (see differ). Extended sense of "apathetic, no more inclined to one thing than to another" first recorded early 15c.; that of "neither good nor bad" is from 1530s, on notion of "neither more nor less advantageous," but since 17c. it has tended toward "rather bad."
indifferently (adv.): late 14c., "alike, equally; indiscriminately;" c.1400, "unconcernedly, carelessly;" early 15c., "impartially, without preferring one to the other;" from indifferent + -ly (2).
indigence (n.): late 14c., from Old French indigence "indigence, need, privation" (13c.), from Latin indigentia "need, want; insatiable desire," from indigentem (nominative indigens) "in want of, needing," present participle of indigere "to need, stand in need of," from indu "in, within" (see indigenous) + egere "be in need, want," from PIE *eg- "to lack" (source also of Old Norse ekla "want, lack," Old High German eccherode "thin, weak").
indigency (n.): 1610s, from Latin indigentia "need, want" (see indigence).
indigene (adj.): 1590s, from French indigène (16c.), from Latin indigena "sprung from the land," as a noun, "a native," literally "in-born" (see indigenous). As a noun from 1660s.
indigenous (adj.): "born or originating in a particular place," 1640s, from Late Latin indigenus "born in a country, native," from Latin indigena "sprung from the land, native," as a noun, "a native," literally "in-born," or "born in (a place)," from Old Latin indu (prep.) "in, within" + gignere (perfective genui) "beget," from PIE root *gene- "to produce, give birth, beget" (see genus).

Indu "within" is from archaic endo, which is cognate with Greek endo- "in, within," from PIE *endo-, extended form of root *en "in" (see in (adv.)). Related: Indigenously.
indigent (adj.): c. 1400, from Old French indigent "poor, needy," from Latin indigentem "in want of, needing" (see indigence). As a noun, "poor person," from early 15c.
indigestible (adj.): late 15c., from Late Latin indigestibilis or else a native formation from in- (1) "not, opposite of" + digestible; or else from Late Latin indigestibilis. Related: Indigestibility (1733).
indigestion (n.): late 14c., "difficulty or inability in digesting food," from Old French indigestion (13c.), from Late Latin indigestionem (nominative indigestio), from in- "not, opposite of" (see in- (1)) + digestionem "arrangement, distribution" (see digestion). An Old English word for it was unmeltung.
indignance (n.): 1580s, from indignant + -ance or else from Medieval Latin indignantia. Indignancy is attested from 1778.
indignant (adj.): 1580s, from Latin indignantem (nominative indignans) "impatient, reluctant, indignant," present participle of indignari "to be displeased at, be offended, resent, deem unworthy" (see indignation). Related: Indignantly.
indignation (n.): c. 1200, from Old French indignacion "fury, rage; disrespect," or directly from Latin indignationem (nominative indignatio) "indignation, displeasure; a provocation, cause for indignation," noun of action from past participle stem of indignari "regard as unworthy, be angry or displeased at," from indignus "unworthy," from in- "not, opposite of" (see in- (1)) + dignus "worthy" (see dignity). The indignation meeting (1835) once was a common American way to express popular outrage by passing and publishing resolutions.
indignity (n.): "unworthy treatment; act intended to lower the dignity of another," 1580s, from Latin indignitatem (nominative indignitas) "unworthiness, meanness, baseness," also "unworthy conduct, an outrage," noun of quality from indignus "unworthy" (see indignation). Related: Indignities.
indigo (n.): 17c. spelling change of indico (1550s), "blue powder obtained from certain plants and used as a dye," from Spanish indico, Portuguese endego, and Dutch (via Portuguese) indigo, all from Latin indicum "indigo," from Greek indikon "blue dye from India," literally "Indian (substance)," neuter of indikos "Indian," from India (see India).

Replaced Middle English ynde (late 13c., from Old French inde "indigo; blue, violet" (13c.), from Latin indicum). Earlier name in Mediterranean languages was annil, anil (see aniline). As "the color of indigo" from 1620s. As the name of the violet-blue color of the spectrum, 1704 (Newton).
indirect (adj.): late 14c., from Old French indirect (14c.) or directly from Late Latin indirectus "not direct," from in- "not, opposite of" (see in- (1)) + directus (see direct (adj.)). Related: Indirectness.
indirection (n.): "irregular means, deceitful action," 1590s, from indirect + -ion.
indirectly (adv.): mid-15c., from indirect + -ly (2).
indiscernible (adj.): 1630s, from in- (1) "not, opposite of" + discernible. Related: Indiscernibly; indiscernibility.
indiscipline (n.): "disorder, lack of discipline," 1783, from in- (1) "not, opposite of" + discipline (n.). Perhaps modeled on French indiscipline (18c.). Indisciplined as a past participle adjective is attested from c. 1400.
indiscreet (adj.): "imprudent, not discrete, lacking good judgment," early 15c., from Medieval Latin indiscretus, from in- "not, opposite of" (see in- (1)) + Latin discretus "separated, distinct" (in Medieval Latin "discerning, careful"), past participle of discernere "distinguish" (see discern). A Medieval Latin secondary sense of the word that also became indiscrete. Related: Indiscreetly; indiscreetness.
indiscrete (adj.): "not containing distinct parts," 1782 (earlier "not distinctly separate," c. 1600), from Latin indiscretus "unseparated; indistinguishable, not known apart," from in- "not, opposite of" (see in- (1)) + discretus "separated, distinct" (in Medieval Latin "discerning, careful"), past participle of discernere "distinguish" (see discern). Related: Indiscretely; indiscreteness.
indiscretion (n.): mid-14c., "want of discretion, imprudence," from Old French indiscrecion "foolishness, imprudence" (12c.), from Late Latin indiscretionem (nominative indiscretio) "lack of discernment," from in- "not, opposite of" (see in- (1)) + discretionem "discernment, power to make distinctions" (see discretion). Meaning "indiscreet act" is from c. 1600.
indiscretionary (adj.): 1788, from indiscretion + -ary.
indiscriminate (adj.): "not carefully discriminating, done without making distinctions," 1640s, from in- (1) "not, opposite of" + discriminate (adj.).
indiscriminately (adv.): 1650s, from indiscriminate + -ly (2).
indispensability (n.): 1640s, from indispensable + -ity.
indispensable (adj.): 1530s, "not subject to dispensation," from Medieval Latin *indispensabilis, from in- "not, opposite of" (see in- (1)) + dispensabilis, from Latin dispensare "disburse, administer, distribute (by weight)" (see dispense). Meaning "necessary" is from 1690s. From 17c. into 19c. often spelled indispensible, but modern dictionaries considered this improper.

As a noun, "indispensable thing," from 1794; c. 1800-1810, after French use, it was the name of a type of pocket bag worn by women. indispensables (1820) also was one of the many 1820s jocular euphemisms for "trousers" (see inexpressible). Related: Indispensably.
indisposed (adj.): c. 1400, "unprepared;" early 15c., "not in order," from in- (1) "not" + disposed; or else from Late Latin indispositus "without order, confused." From mid-15c. in English as "diseased;" modern sense of "not very well, slightly ill" is from 1590s. A verb indispose is attested from 1650s but perhaps is a back-formation of this, rather than its source, or from French indisposer.
indisposition (n.): early 15c., "unfavorable influence" (in astrology), mid-15c., "disinclination (to), state of being not disposed in mind," from in- (1) "not, opposite of" + disposition. Perhaps modeled on Old French indisposicion or Medieval Latin indispositio. Sense of "ill health, disorder of the mind or body" is from mid-15c. Other 15c. senses included "inclination to evil; wickedness," and "public disorder, lawlessness."
indisputable (adj.): 1550s, from Late Latin indisputabilis, from in- "not, opposite of, without" (see in- (1)) + disputabilis, from Latin disputare "to weigh, examine, discuss, argue, explain" (see dispute (v.)). Related: Indisputably.
indissolubility (n.): 1670s, from indissoluble + -ity.
indissoluble (adj.): mid-15c. (implied in indissolubly), from Latin indissolubilis "indestructible, that cannot be dissolved," from in- "not, opposite of" (see in- (1)) + dissolubilis, from dis- + solubilis (see soluble). Related: Indissolubly.
indistinct (adj.): 1580s, "not seen or heard clearly," from Latin indistinctus "not distinguishable, confused, obscure," from in- "not, opposite of" (see in- (1)) + distinctus (see distinct). From c. 1600 as "not clearly defined or distinguished." Indistinctly is attested from c. 1400 in an obsolete sense "equally, alike, indiscriminately." Related: Indistinctness.
indistinguishable (adj.): 1640s, "not clearly perceived;" 1650s, "incapable of being told apart," from in- (1) "not, opposite of" + distinguishable. Shakespeare's use of it (c. 1600) seems to mean "of indeterminate shape." Related: Indistinguishably.
indite (v.): formerly also endite, late 14c., "put down in writing," from Old French enditer, enditier "dictate, write; draw up, draft; (legally) indict," from Vulgar Latin *indictare, from Latin in- "in, into, on, upon" (see in- (2)) + dictare "to declare" (see dictate (v.)). The same word as indict but retaining a French form. Related: Indited; inditing.