squealer

a person who provides information about another's wrongdoing after finding out who told on them, the hoodlums proceeded to give the squealer the beating of his life Synonyms betrayer, canary [slang], deep throat, fink, informant, nark [British], rat, rat fink, snitch, snitcher, informer, stoolie, stool pigeon, talebearer, tattler, tattletale, telltale, whistle-blowerRelated Words collaborator; blabber, blabbermouth, gossip, gossiper, leaker; snoop, snooper, spy; notifier