a person who pretends to have virtues, moral or religious beliefs, principles, etc., that he or she does not actually possess, esp. a person whose actions belie stated beliefs.

a person who feigns some desirable or publicly approved attitude, esp. one whose private life, opinions, or statements belie his or her public statements.

noun

actor , attitudinizer , backslider , bigot , bluffer , casuist , charlatan , cheat , con artist , crook , deceiver , decoy , dissembler , dissimulator , fake , faker , four-flusher , fraud , hook * , humbug , impostor , informer , lip server , malingerer , masquerader , mountebank , pharisee , phony , playactor , poser , pretender , quack * , smoothie , sophist , swindler , trickster , two-face , two-timer , wolf in sheep’s clothing , tartuffe , formalist , poseur , quack