delusive, false -- (inappropriate to reality or facts; "delusive faith in a wonder drug"; "delusive expectations"; "false hopes")
fake, false, faux, imitation, simulated -- (not genuine or real; being an imitation of the genuine article; "it isn't fake anything; it's real synthetic fur"; "faux pearls"; "false teeth"; "decorated with imitation palm leaves"; "a purse of simulated alligator hide")
false -- (designed to deceive; "a suitcase with a false bottom")
false, off-key, sour -- (inaccurate in pitch; "a false (or sour) note"; "her singing was off key")
assumed, false, fictitious, fictive, pretended, put on, sham -- (adopted in order to deceive; "an assumed name"; "an assumed cheerfulness"; "a fictitious address"; "fictive sympathy"; "a pretended interest"; "a put-on childish voice"; "sham modesty")
false, untrue -- ((used especially of persons) not dependable in devotion or affection; unfaithful; "a false friend"; "when lovers prove untrue")