2. premise, antecedent, ground, basis, foundation, starting point.
3. assumption, supposal, supposition, presupposition, presumption, inference; conjecture, speculation, SI. guesstimate, guess, rough guess, wild guess, blind guess, Inf. stab, Inf. shot, Inf. shot in the dark; notion, thought, idea, fancy, imagining.
hypothesize, v. postulate, post, predicate, theorize, hypothecate; offer, submit, put forward, extend; conjecture, guess, surmise, assume, presume, suppose, presuppose; infer, deduce, conclude, find.
hypothetical, adj. 1. supposed, assumed, presumed, reputed, putative, inferred; guessed, conjectured, surmised, suspected, imagined; debatable, questionable, doubtful, problematic, uncertain, undetermined.