THESAURUS
strikebreaker
apostate, backslider, blackleg, bolter, collaborationist, collaborator, convert, defector, deserter, fifth columnist, fink, mugwump, proselyte, quisling, rat, recidivist, recreant, renegade, renegado, renegate, reversionist, runagate, scab, schismatic, seceder, secessionist, separatist, tergiversant, tergiversator, traitor, turnabout, turncoat, turntail