poseur

copycat, imitator, impersonator, mimic

charlatan, fake, faker, fakir, fraud, hoaxer, humbug, impostor, mountebank, phony (also phoney), pretender, quack, quacksalver, ringer, sham

actor, bluffer, counterfeiter, deceiver, dissembler, duper, feigner, misleader, operator, trickster

cozener, defrauder, dodger, fraudster [chiefly British], scammer, scamster, sharper, sharpie (or sharpy), skinner, swindler