[n] a very loud utterance (like the sound of an animal); "his bellow filled the hallway"
[n] a deep prolonged loud noise
[adv] extremely; "roaring drunk"
[adj] loud enough to cause (temporary) hearing loss
[adj] very lively and profitable; "flourishing businesses"; "a palmy time for stockbrokers"; "a prosperous new business"; "doing a roaring trade"; "a thriving tourist center"; "did a thriving business in orchids"
bellow, bellowing, boom, booming, deafening, earsplitting, flourishing, holla, holler, hollering, hollo, holloa, loud, palmy, prospering, prosperous, roar, roar, successful, thriving, thunder, thunderous, thundery, yowl