(n.) A quack; an impostor\; one who prates much in his own favor, and makes unwarrantable pretensions; an empiric; a mountebank.

blagueur bluff bluffer charlatanic charlatanish fake faker fourflusher fraud horse doctor humbug impersonator impostor malingerer medicaster medicine man medicine monger mountebank phony poser poseur pretender quack quackish quacksalver quackster ringer saltimbanco sham shammer