The Collaborative International Dictionary of English v.0.48:
Annihilative \An*ni"hi*la*tive\, a. Serving to annihilate; destructive. [1913 Webster]WordNet (r) 3.0 (2006):
annihilative adj 1: wreaking or capable of wreaking complete destruction; "possessing annihilative power"; "a devastating hurricane"; "the guns opened a withering fire" [syn: annihilative, annihilating, devastating, withering]