WordNet sense 1 (a sudden happening that brings good fortune (as a sudden opportunity to make money)):

bonanza, godsend, gravy, windfall, bunce, gold rush, manna from heaven

WordNet sense 2 (a deep prolonged loud noise):

roar, roaring, thunder

WordNet sense 3 (a pole carrying an overhead microphone projected over a film or tv set):

microphone boom

WordNet sense 4 (make a resonant sound, like artillery):

din

WordNet sense 5 (make a deep hollow sound):

boom out

WordNet sense 6 (hit hard):

blast, nail, smash

WordNet sense 7 (grow stronger):

expand, flourish, prosper, thrive, get ahead