backstabber

one who betrays a trust or an allegiance a backstabber taking credit for work she didn't do while bad-mouthing the rest of the team to the boss Synonyms apostate, traitor, 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