noun (n)

• a person who professes beliefs and opinions that he or she does not hold in order to conceal his or her real feelings or motives(noun.person)

  Synonym:
  dissimulator, hypocrite, phoney, phony, pretender
  

  source: wordnet30
• One who dissembles; one who conceals his opinions or dispositions under a false appearance; a hypocrite.(noun)

  source: webster1913