apostate

1 a person who abandons a cause or organization usually without right an apostate from communism, he later became one of its harshest critics Synonyms renegade, defector, deserter, recreantRelated Words betrayer, double-crosser, quisling, traitor, traitress (or traitoress), turnabout, turncoat; abandoner, come-outer, dropout, leaver; defier, insurgent, insurrectionary, insurrectionist, mutineer, rebel, red, revolter, revolutionary, revolutionist, revolutionizer; discontent, malcontent; recusant, refusenik (also refusnik), refuserNear Antonyms adherent, disciple, follower, supporter; fanatic, militant, partisan (also partizan), zealotAntonyms loyalist

2 one who betrays a trust or an allegiance became an apostate to liberalism after he had gotten wealthy Synonyms traitor, backstabber, betrayer, double-crosser, double-dealer, Judas, quisling, recreant, serpent, snake, turncoatRelated Words accommodationist, collaborationist, collaborator, sellout, subversive, subverter; coconspirator, conspirator, intriguer, plotter, schemer; defector, deserter, renegade; blabbermouth, gossip, gossiper, gossipmonger, informant, informer, rat, rumormonger, snitch, snitcher, squealer, stool pigeon, talebearer, talker, tattler, tattletale, telltale