2
unfounded
2
unobtainable(adjective, impossible)
2
unreliable(adjective, true, unpredictable, fickle, variable)
2
unsatisfactory(adjective, poor, thin, false, small)
2
unsound(adjective, false, unreasonable, senseless, unpredictable)
2
unworkable(adjective, impossible)
1
apocryphal
1
astonishing(extraordinary, amazing, incredible)
1
baseless(adjective, poor, unconvincing)
1
cockamamie(extraordinary, amazing, incredible)
1
cockeyed(extraordinary, amazing, irrational, incredible, unreasoned)
1
contradictory(adjective, absurd)
1
deficient(adjective, flat, poor, thin, small)
1
doubtable
1
eccentric(adjective, absurd)
1
exaggerated(adjective, hard, keen, sharp, difficult)
1
extraordinary(strange, amazing, unbelievable, incredible, unthinkable)
1
false(adjective, poor, thin, unreasonable, senseless)
1
far out(expression, adjective, likely, unlikely, unbelievable)
1
fictitious
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APASmart Define. (2015). implausible thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/implausible/thesaurus/synonyms
ChicagoSmart Define. 2015. "implausible thesaurus" https://smartdefine.org/implausible/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, implausible thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/implausible/thesaurus/synonyms>.
MLASmart Define. "implausible thesaurus" 14 April 2015. Web. 22 September 2026. <https://smartdefine.org/implausible/thesaurus/synonyms>