WordNet sense 1 (a copy that is represented as the original):

forgery, imitation

WordNet sense 2 (make a copy of with the intent to deceive):

forge

WordNet sense 3 ((often used in combination) not genuine but having the appearance of):

pseudo

WordNet sense 4 (serving as an imitation or substitute):

pinchbeck

WordNet sense 5 (constituting a copy or imitation of something):

mock

WordNet sense 6 (intended to deceive):

spurious

WordNet sense 7 (fraudulent; having a misleading appearance):

bogus, fake, phony

WordNet sense 8 (reproduced fraudulently):

forged

WordNet sense 9 (adopted in order to deceive):

assumed, fictitious, sham, false, put on

WordNet sense 10 (not genuine; imitating something superior):

imitative