To annihilate something means to destroy it completely. The Army was annihilated. + annihilation an·ni·hi·la·tion the threat of nuclear war and annihilation of the human race
To destroy or eradicate, as a property or attribute of a thing; to make of no effect; to destroy the force, etc
If you annihilate someone in a contest or argument, you totally defeat them. The Dutch annihilated the Olympic champions 5-0
To reduce to nothing or nonexistence; to destroy the existence of; to cause to cease to be
To destroy the form or peculiar distinctive properties of, so that the specific thing no longer exists; as, to annihilate a forest by cutting down the trees