verb (used with object), an·ni·hi·lat·ed, an·ni·hi·lat·ing.
- to reduce to utter ruin or nonexistence; destroy utterly: The heavy bombing almost annihilated the city.
- to destroy the collective existence or main body of; wipe out: to annihilate an army.
- to annul; make void: to annihilate a law.
- to cancel the effect of; nullify.
- to defeat completely; vanquish: Our basketball team annihilated the visiting team.
- (tr) to destroy completely; extinguish
- (tr) informal to defeat totally, as in debate or argument
- (intr) physics to undergo annihilation
1520s, from an obsolete adjective meaning “reduced to nothing” (late 14c.), originally the past participle of a verb, anihil, from Old French annichiler (14c.), from Late Latin annihilare “to reduce to nothing,” from Latin ad- “to” (see ad-) + nihil “nothing” (see nil). Related: Annihilated; annihilating.