Contra (contro, counter), against; contradict, contravene, controversy, controvert, contraband, counterfeit.
De, down or from; denote, describe, depart, descent, devise, demure.
Dis (dif, di); disjoin, difficult, diffuse, divide, differ, dilute, dissent.
Ex (ef, e), out of; extort, exhume, efface, educe, extrude, extol, effect, education.
Extra, beyond; extraordinary, extravagant, extraneous.
In (il, im, ir, em, en), into; invade, incite, induce, illusion, illude, improve, impulse, impel, irruption, embrace, endure, encourage, embroil, irradiate, innate.
In (ig, il, im, ir), not; insecure, ignoble, illiterate, inconvenient, incurable, incapable, incapacitate, immortal, irregular, improper, illegitimate, irrational, innocent, infant.
Inter (intel, enter), between; intercourse, intelligent, interfere, interdict, enterprise, entertain, interrupt.
Intro, within; introduce.
Ob (oc, of, op, os), against; oblige, obtain, object, occur, offend, oppose, occult, offer, ostentation.