WordNet sense 1 (imagined as in a play):

make-believe

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

unreal

WordNet sense 3 (behave unnaturally or affectedly):

act, dissemble

WordNet sense 4 (put forward, of a guess, in spite of possible refutation):

guess, hazard, venture

WordNet sense 5 (represent fictitiously, as in a play, or pretend to be or act like):

make

WordNet sense 6 (make believe with the intent to deceive):

affect, feign, sham, affect

WordNet sense 7 (state insincerely):

profess