44 entries under implausible topic. ×

25
inconceivable(adjective, belief, unreasonable, useless, size)
25
incredible(adjective, great, excellent, belief, superb)
15
impossible(adjective, extraordinary, strange, amazing)
11
improbable(adjective, great, excellent, superb, super)
10
preposterous(adjective, extraordinary, unreasonable, useless, absurd)
7
rare(adjective, light, extraordinary, strange, exceptional)
6
doubtful(adjective, extraordinary, amazing, dubious, unlikely)
6
fanciful(great, excellent, superb, super, doubtful)
6
unlikely(adjective, light, extraordinary, strange, rare)
5
absurd(adjective, unreasonable, useless, doubtful, dubious)
5
beyond belief(expression, adjective, idiom, extraordinary, belief)
4
dubious(adjective, extraordinary, amazing, doubtful, unlikely)
4
ridiculous(adjective, unbelievable, improbable, unfeasible)
4
unconvincing(adjective, extraordinary, strange, amazing, doubtful)
4
unknowable(adjective, extraordinary, strange, unfathomable)
3
mind-boggling(adjective, extraordinary, strange, amazing, unbelievable)
2
far-fetched(adjective, extraordinary, amazing, doubtful, unlikely)
2
outlandish(extraordinary, exceptional, amazing, remarkable, particular)
2
questionable(extraordinary, amazing, doubtful, dubious, unlikely)
2
suspect(extraordinary, amazing, unbelievable, incredible)
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APASmart Define. (2015). unimaginable thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/unimaginable/thesaurus/synonyms
ChicagoSmart Define. 2015. "unimaginable thesaurus" https://smartdefine.org/unimaginable/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2015, unimaginable thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/unimaginable/thesaurus/synonyms>.
MLASmart Define. "unimaginable thesaurus" 14 April 2015. Web. 23 September 2026. <https://smartdefine.org/unimaginable/thesaurus/synonyms>