betrayer

betrayer
    n 1: one who reveals confidential information in return for
         money [syn: {informer}, {betrayer}, {rat}, {squealer},
         {blabber}]
    2: a person who says one thing and does another [syn: {double-
       crosser}, {double-dealer}, {two-timer}, {betrayer},
       {traitor}]
    

Betrayer \Be*tray"er\, n.
   One who, or that which, betrays.
   [1913 Webster]
    

79 Moby Thesaurus words for "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