33 entries under implausible topic. ×

15
preposterous(adjective, false, ridiculous, absurd, bizarre)
13
incredible(adjective, extraordinary, strange, unreasonable, unbelievable)
11
unbelievable(adjective, hard, extraordinary, strange, unreasonable)
9
unlikely(adjective, extraordinary, unusual, strange, unreasonable)
6
outlandish(adjective, hard, difficult, extraordinary, silly)
3
far-fetched(adjective, extraordinary, amazing, unlikely)
3
questionable(adjective, extraordinary, amazing, unlikely, unbelievable)
2
fantastic(extraordinary, false, strange, silly)
2
staggering(adjective, extraordinary, strange, amazing, unbelievable)
2
suspect(extraordinary, unreasonable, amazing, dubious, unlikely)
2
untenable(unbelievable, improbable)
1
beyond belief(expression, adjective, extraordinary, amazing)
1
beyond reason(expression, extraordinary, strange, unbelievable)
1
extraordinary(strange, amazing, unbelievable, incredible)
1
fishy(adjective, extraordinary, unreasonable, amazing, dubious)
1
flimsy(extraordinary, unreasonable, amazing, dubious, unlikely)
1
imcomprehensible(extraordinary, strange, unbelievable, unthinkable)
1
incogitable(extraordinary, strange, amazing, unbelievable)
1
insupposable(extraordinary, strange, unbelievable, improbable)
1
mind-boggling(adjective, extraordinary, strange, amazing, unbelievable)
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APASmart Define. (2016). impossible thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/impossible/thesaurus/synonyms
ChicagoSmart Define. 2016. "impossible thesaurus" https://smartdefine.org/impossible/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2016, impossible thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/impossible/thesaurus/synonyms>.
MLASmart Define. "impossible thesaurus" 9 March 2016. Web. 22 September 2026. <https://smartdefine.org/impossible/thesaurus/synonyms>