conjecture, doubt, guess, guesswork, hypothesis, idea, notion, postulate, presumption, speculation, surmise, theory
English Collins Dictionary - English synonyms & Thesaurus
supposition ( suppositions plural )
1 n-count A supposition is an idea or statement which someone believes or assumes to be true, although they may have no evidence for it.
FORMAL oft N that
There's a popular supposition that we're publicly funded but the bulk of our money comes from competitive contracts...
2 n-uncount You can describe someone's ideas or statements as supposition if you disapprove of the fact that they have no evidence to support them., (disapproval)
The report has been rejected by the authorities, who said much of it was based on supposition or inaccuracy.
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