Word Study
fifth columnist
THESAURUS
fifth columnist
Trojan horse, apostate, backslider, bolter, collaborationist, collaborator, convert, crypto, defector, deserter, fellow traveler, fifth column, fraternizer, mugwump, proselyte, quisling, recidivist, recreant, renegade, renegado, renegate, reversionist, runagate, saboteur, schismatic, seceder, secessionist, security risk, separatist, strikebreaker, subversive, tergiversant, tergiversator, traitor, turnabout, turncoat, turntail, undergroundFor further exploring for "fifth columnist" in Webster Dictionary Online