32 entries under implausible topic. ×

26
incredible(adjective, great, excellent, belief, superb)
20
impossible(noun, adjective, extraordinary, unusual, strange)
17
improbable(adjective, great, excellent, unusual, superb)
12
unlikely(adjective, light, thin, extraordinary, unusual)
11
preposterous(adjective, unusual, unreasonable, useless, ridiculous)
10
rare(adjective, extraordinary, unusual, strange, exceptional)
9
ridiculous(adjective, absurd, outrageous, unbelievable)
7
beyond belief(expression, adjective, idiom, unusual, belief)
5
mind-boggling(adjective, extraordinary, strange, amazing, unbelievable)
5
staggering(adjective, great, excellent, superb, super)
4
outlandish(adjective, extraordinary, unusual, exceptional, absurd)
4
questionable(adjective, extraordinary, amazing, unbelievable)
4
unconvincing(adjective, extraordinary, strange, amazing)
4
unheard-of(adjective, extraordinary, strange, exceptional, marvelous)
3
far-fetched(adjective, extraordinary, amazing, unbelievable)
2
incogitable(adjective, extraordinary, unusual, strange, amazing)
2
suspect(extraordinary, amazing, unbelievable, incredible)
2
thin(adjective, light, extraordinary, strange, amazing)
1
belief(adjective, extraordinary, strange, unbelievable)
1
beyond reason(expression, adjective, extraordinary, strange, unbelievable)
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APASmart Define. (2015). unthinkable thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/unthinkable/thesaurus/synonyms
ChicagoSmart Define. 2015. "unthinkable thesaurus" https://smartdefine.org/unthinkable/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, unthinkable thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/unthinkable/thesaurus/synonyms>.
MLASmart Define. "unthinkable thesaurus" 14 April 2015. Web. 22 September 2026. <https://smartdefine.org/unthinkable/thesaurus/synonyms>