illegitimate a. not according to law; not regular or authorized; unlawful; improper | 
illustrious a. possessing luster or brightness; brilliant; luminous; splendid | 
impeach v. make an accusation against; challenge or discredit the credibility of | 
imperative n. having power command or control; critically importance; some duty that is essential and urgent | 
imperial a. like an emperor; related to an empire; ruling over extensive territories | 
impertinent a. improperly forward or bold; rude | 
impoverish v. make poor; reduce to poverty or indigence; exhaust the strength, richness, or fertility of | 
impregnate v. infuse or fill completely; fertilize and cause to grow; make pregnant | 
inaccessible a. unreachable; not available; unattainable | 
incandescent a. strikingly bright; shining with intense heat; emitting light as result of being heated | 
incision n. cutting into a substance; cut into a body tissue or organ, especially one made during surgery | 
inclination n. preference; tendency; inclined surface; slope | 
inclusive a. tending to include all; taking a great deal or everything within its scope | 
incorporate v. combine something into a larger whole; unite | 
incriminate v. accuse of a crime or other wrongful act; suggest that someone is guilty | 
indemnify v. make amends for; pay compensation for; secure against future loss, damage, or liability | 
indisposed a. averse; disinclined; unwilling to do a task | 
induce v. persuade; bring about; reason or establish by induction | 
inducement n. something that helps bring about an action or a desired result; an incentive | 
inert a. inactive; lacking power to move; unable to move or act | 
inevitable a. unavoidable;  incapable of being avoided or prevented | 
infatuate v. arouse unreasoning love or passion in and cause to behave in an irrational way | 
infernal a. pertaining to hell; devilish; abominable; awful | 
inkling n. slight hint or indication; slight understanding | 
innumerable a. too many to be counted; numerous | 
inquisitive a. disposed to ask questions, especially in matters which do not concern the inquirer; given to examination, investigation, or research | 
insufferable a. incapable of being suffered, borne, or endured; insupportable; unendurable; intolerable | 
integral a. essential or necessary for completeness; entire | 
intolerable a. incapable of being put up with; unable to be endured | 
intolerant a. not enduring; not able to endure; unwilling to tolerate difference of opinion | 
intuition n. immediate insight; power of knowing without reasoning | 
inundate v. overwhelm;  cover with water, especially floodwaters | 
invertebrate n. animal, such as an insect, that lacks backbone or spinal column | 
invincible a. incapable of being overcome or defeated; unconquerable | 
invoke v. call upon; ask for; request earnestly | 
ire n. anger; wrath; keen resentment; irritate | 
irony n. expression by deliberate contrast between apparent and intended meaning; witty language used to insult | 
irreducible a. incapable of being made smaller or simpler | 
jargon n. language used by a special group; technical terminology; nonsensical or meaningless talk | 
kinetic a. relating to, or produced by motion; dynamic | 
lateral a. coming from side; situated at or extending to the side | 
laud v. give praise to; glorify; celebrate or honor | 
legacy n. gift made by a will; something handed down from an ancestor | 
liberalism n. a political orientation that favors social progress by reform and by changing laws rather than by revolution | 
linear a. having form of a line; straight; consisting of lines; lineal | 
linguistics n. humanistic study of language and literature | 
liquidate v. settle accounts to pay them off; clear up | 
listless a. lacking in spirit or energy to exert effort | 
lucid a. easily understood; expressed clearly; bright or luminous | 
mainstay n. a prominent supporter; a central cohesive source of support and stability | 
malady n. disease, disorder, or ailment; unwholesome condition | 
manipulate v. operate with one's hands; control or play upon people, forces artfully | 
manor n. the mansion of a lord or wealthy person; the landed estate of a lord | 
materialize v. come into being; become reality | 
maternal a. motherly; relating to mother or motherhood | 
maudlin a. tearfully sentimental; over-emotional; sickly-sentimental | 
maul v. handle someone or something in a rough way; cause serious physical wounds | 
mechanization n. the condition of having a highly technical implementation; the act of implementing the control of equipment with advanced technology | 
medley n. mixture; musical composition consisting of a series of  pieces | 
mendicant n. beggar; religious friar forbidden to own personal property who begs for living | 
metaphysical a. without material form or substance; based on abstract reasoning; highly abstract or theoretical; supernatural | 
minutiae n. petty details; small particular or detail; a minute or trivial matter of fact |