1
chance in a million
1
closed-out
1
cockamamie(extraordinary, amazing, incredible)
1
cockeyed(extraordinary, amazing, incredible)
1
contraband
1
curious(extraordinary, unusual, exceptional, marvelous, special)
1
disgraceful
1
doubtable
1
dubitable
1
egregious(unusual, special, rare)
1
excessively
1
excluded
1
farfetched
1
fishy(adjective, extraordinary, amazing, unbelievable, implausible)
1
flaky(extraordinary, amazing, incredible)
1
flimsy(light, thin, extraordinary, strange, rare)
1
for the birds(expression, idiom, extraordinary, amazing, incredible)
1
full of holes(expression, idiom, extraordinary, amazing, incredible)
1
ghost of a chance
1
hard of belief(expression, idiom)
11 years ago|5.6k views|share |citing 
APASmart Define. (2015). unthinkable thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/unthinkable/thesaurus/synonyms
ChicagoSmart Define. 2015. "unthinkable thesaurus" https://smartdefine.org/unthinkable/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, unthinkable thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/unthinkable/thesaurus/synonyms>.
MLASmart Define. "unthinkable thesaurus" 14 April 2015. Web. 25 September 2026. <https://smartdefine.org/unthinkable/thesaurus/synonyms>