71 entries under implausible topic. ×

33
unlikely(adjective, slight, extraordinary, strange, superb)
26
incredible(adjective, great, excellent, flat, poor)
26
unbelievable(adjective, great, excellent, flat, poor)
17
doubtful(adjective, extraordinary, uncertain, fantastic, dubious)
16
questionable(adjective, uncertain, doubtful, dubious, likely)
16
unthinkable(adjective, great, excellent, unusual, superb)
15
dubious(adjective, uncertain, doubtful, likely, unlikely)
14
inconceivable(adjective, great, flat, poor, thin)
14
unconvincing(adjective, great, flat, poor, thin)
14
unimaginable(adjective, great, excellent, superb, super)
12
far-fetched(adjective, hard, extraordinary, uncertain, fantastic)
11
extraordinary(great, excellent, strange, superb, super)
10
weak(adjective, great, poor, extraordinary, strange)
9
fishy(adjective, uncertain, unreasonable, doubtful, dubious)
8
flimsy(adjective, poor, thin, informal, unreasonable)
8
thin(adjective, weak, great, poor, extraordinary)
6
ridiculous(adjective, unbelievable)
5
preposterous(adjective, extraordinary, fantastic, amazing, unbelievable)
5
rare(adjective, extraordinary, strange, doubtful, dubious)
5
strange(adjective, extraordinary, fantastic, doubtful, dubious)
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APASmart Define. (2015). improbable thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/improbable/thesaurus/synonyms
ChicagoSmart Define. 2015. "improbable thesaurus" https://smartdefine.org/improbable/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2015, improbable thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/improbable/thesaurus/synonyms>.
MLASmart Define. "improbable thesaurus" 14 April 2015. Web. 21 September 2026. <https://smartdefine.org/improbable/thesaurus/synonyms>