WordNet sense 1 (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):

dissembler, dissimulator, hypocrite, phoney, pretender

WordNet sense 2 (fraudulent; having a misleading appearance):

bogus, fake

WordNet sense 3 (not genuine; imitating something superior):

counterfeit, imitative