sup·po·si·tious /-ˈzɪʃəs/
suppositious
adj : based primarily on surmise rather than adequate evidence;
"theories about the extinction of dinosaurs are still
highly conjectural"; "the supposed reason for his
absence"; "suppositious reconstructions of dead
languages"; "supposititious hypotheses" [syn: conjectural,
divinatory, supposed, suppositional, supposititious]