Word Study
suppositious
OXFORD DICTIONARY
suppositious, adj. hypothetical, assumed.
Derivative
suppositiously adv. suppositiousness n.
Etymology
partly f. SUPPOSITITIOUS, partly f. SUPPOSITION + -OUS
ROGET THESAURUS
suppositious
Supposition
N supposition, assumption, assumed position, postulation, condition, presupposition, hypothesis, blue sky hypothesis, postulate, postulatum, theory, thesis, theorem, data, proposition, position, proposal, presumption, divination, conjecture, guess, guesswork, speculation, rough guess, shot, shot in the dark, conjecturality, surmise, suspicion, sneaking suspicion, estimate, approximation (nearness), inkling, suggestion, hint, intimation, notion, impression, bare supposition, vague supposition, loose supposition, loose suggestion, association of ideas, (analogy), metonym, metonymy, simile (metaphor), conceit, idea, thought, original idea, invention (imagination), supposing, given, mooted, postulatory, assumed, supposititious, suppositive, suppositious, gratuitous, speculative, conjectural, hypothetical, theoretical, academic, supposable, presumptive, putative, suppositional, suggestive, allusive, if, if so be, an, on the supposition, ex hypothesi, in the case, in the event of, quasi, as if, provided, perhaps, for aught one knows.For further exploring for "suppositious" in Webster Dictionary Online