Synonyms and related words :
Brutus, Judas, Judas Iscariot, Quisling, archtraitor, betrayer, cockatrice, conniver, conspirator, conspirer, double agent, double-crosser, double-dealer, informer, intrigant, intriguer, machinator, plotter, quisling, rat, schemer, serpent, snake, timeserver, traitor, treasonist, trimmer, turncoat