86 entries under adjective topic. ×

5
doubtful(extraordinary, amazing, incredible)
5
dubious(extraordinary, amazing, incredible)
5
mind-boggling(extraordinary, strange, amazing, unbelievable)
5
staggering(great, excellent, superb, super)
4
fanciful(great, excellent, superb, super)
4
illogical(unusual, incredible)
4
mind-blowing(unbelievable, unimaginable)
4
outlandish(extraordinary, unusual, exceptional, absurd)
4
overwhelming(great, excellent, superb, super)
4
questionable(extraordinary, amazing, unbelievable, implausible)
4
unconvincing(extraordinary, strange, amazing, implausible)
4
unheard-of(extraordinary, strange, exceptional, marvelous)
4
unordinary(excellent, extraordinary, unusual, exceptional)
4
untold
4
unworkable(possible, impossible)
3
far-fetched(extraordinary, amazing, unbelievable, implausible)
3
hopeless
3
impracticable
3
incomprehensible
3
ludicrous
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APASmart Define. (2015). unthinkable thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/unthinkable/thesaurus/synonyms
ChicagoSmart Define. 2015. "unthinkable thesaurus" https://smartdefine.org/unthinkable/thesaurus/synonyms (accessed September 27, 2026).
HarvardSmart Define 2015, unthinkable thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/unthinkable/thesaurus/synonyms>.
MLASmart Define. "unthinkable thesaurus" 14 April 2015. Web. 27 September 2026. <https://smartdefine.org/unthinkable/thesaurus/synonyms>