| Term | Definition |
| infringe | v.violate,encroach |
| ingenuous | adj. naive and trusting; young; unsophisticated |
| ingrained | adj. deeply established; firmly rooted |
| ingrate | n. ungrateful person |
| ingratiate | v. become popular with |
| inherent | adj. firmly established by nature or habit |
| inhibit | v. restrain; retard or prevent |
| inimical | adj. unfriendly; hostile; hramful; detrimental |
| inimitable | adj. matchless; not able to be imitated |
| iniquitous | adj. wicked; immoral; unrighteous |
| initiate | v. begin; originate; receive into a group |
| injurious | adj. harmful |
| inkling | n. hint |
| innate | adj. inborn |
| innocuous | adj. harmless |
| innovation | n. change; introduction of something new |
| ingenious | adj. clever;resourceful |
| innuendo | n. hint; insinuation |
| inopportune | adj. untimely; poorly chosen |
| inordinate | adj. unrestrained; excessive |
| inquisitor | n. questioner (especially harsh); investigator |
| insalubrious | adj. unwholesome; not healthful |
| insatiable | adj. not easily satisfied; unquenchable; greedy |
| inscrutable | adj. impenetrable; not readily understood; mysterious |
| insensible | adj. unconscious; unresponsive |
| insidious | adj. treacherous; stealthy; sly |
| insightful | adj. discerning; perceptive |
| insinuate | v. hint; imply; creep in |
| insipid | adj. lacking in flavor; dull |
| insolence | n. impudent disrespect; haughtiness |
| insolvent | adj. bankrupt; unable to repay one's debt |
| insomnia | n. wakefulness; inability to sleep |
| instigate | v. urge; start; provoke |
| insubordination | n. disobedience; rebelliousness |
| insubstantial | adj. lacking substance; insignificant; frail |
| insularity | n. narrow-mindedness; isolation |
| insouciant | adj. indifferent;without concern or care |
| insuperable | adj. insurmountable; unbeatable |
| insurgent | adj. rebellious |
| insurmountable | adj. overwhelming; unbeatable; insuperable |
| insurrection | n. rebellion; uprising |
| intangible | adj. not able to be perceived by touch; vague |
| integral | adj. complete; necessary for completeness |
| integrate | v. make whole; combine; make into one unit |
| integrity | n. uprightness; wholeness |
| intellect | n. higher mental powers |
| intelligentsia | n. the intelligent and educated classes (often used derogatorily) |
| insensate | adj.without feeling |
| inter | v. bury |
| interim | n. meantime |
| interloper | n. intruder; unwanted meddler |
| interment | n. burial |
| intermittent | adj. periodic; on and off |
| interrogate | v. question closely; cross-examine |
| intervene | v. come between |
| intimate | v. hint; suggest |
| intimidate | v. frighten |
| intractable | adj. unruly; stubborn; unyielding |
| intransigence | n. refusal of any compromise; stubbornness |
| intrepid | adj. fearless |
| intrinsic | adj. essential; inherent; built-in |
| introspective | adj. looking within oneself |
| introvert | n. one who is introspective; inclined to think more about oneself |
| intrude | v. trespass; enter as an uninvited person |
| intuition | n. immediate insight; power of knowing without reasoning |
| inundate | v. overwhelm; flood; submerge |
| inured | adj. accustomed; hardened |
| invalidate | v. weaken; destroy |
| interdict | v.prohibit;forbid |
| invective | n. abuse |
| inverse | adj. opposite |
| invert | v. turn upside down or inside out |
| internecine | adj.mutually destructive |
| interpolate | v.insert between |
| interregnum | n.period b/w two reigns |
| inveigh | v.denounce;utter censure or invective |
| inveigle | v.lead astray;wheedle |