WordNet sense 1 (formed or conceived by the imagination):

fictional, made-up, fabricated, fancied, invented

WordNet sense 2 (lacking in reality or substance or genuineness; not corresponding to acknowledged facts or criteria):

unreal

WordNet sense 3 (adopted in order to deceive):

assumed, fictive, sham, false, pretended, put on

WordNet sense 4 (not genuine; imitating something superior):

counterfeit, imitative