THESAURUS
betrayer
Benedict Arnold, Brutus, Judas, Judas Iscariot, Quisling, archtraitor, blab, blabber, blabberer, blabbermouth, cockatrice, conniver, conspirator, conspirer, convict, criminal, crook, debaucher, deceiver, defiler, delator, desperado, desperate criminal, despoiler, double agent, double-crosser, double-dealer, felon, fink, fugitive, gallows bird, gangster, gaolbird, informer, intrigant, intriguer, jailbird, lawbreaker, machinator, mobster, narc, nark, outlaw, peacher, plotter, public enemy, quisling, racketeer, raper, rapist, rat, ravager, ravisher, schemer, scofflaw, seducer, serpent, snake, snitch, snitcher, spy, squealer, stool pigeon, stoolie, swindler, talebearer, tattler, tattletale, telltale, thief, thug, timeserver, traitor, treasonist, trimmer, turncoat, two-timer, violator, whistle-blower
ROGET THESAURUS
betrayer
Knave
N
knave, rogue, Scapin, rascal, Lazarillo de Tormes, bad man, blackguard, barrater, barrator, shyster, traitor,
betrayer, archtraitor, conspirator, Judas, Catiline, reptile, serpent, snake in the grass, wolf in sheep's clothing, sneak, Jerry Sneak, squealer, tell-tale, mischief-maker, trimmer, fence-sitter, renegade, truant, recreant, sycophant.