Synonyms for Terrific (same or very similar meaning)
WordNet sense 1 (extraordinarily good; used especially as intensifiers):
fantastic, grand, howling, marvelous, rattling, tremendous, wonderful, wondrous, marvellousWordNet sense 2 (in an extreme degree):
intenseWordNet sense 3 (causing extreme terror):
terrifyingWordNet sense 4 (causing alarm or fear):
alarmingFrom the ODE community, based on WordNetadd/edit