5
self-contradictory(adjective, absurd)
5
unobtainable
5
unsuitable(adjective, intolerable, ungovernable)
4
crazy(adjective, absurd)
4
contrary to reason(expression, adjective, idiom, inaccessible, impossibility)
4
farcical(adjective, absurd)
4
futile(adjective, desperate, unpromising, unfeasible, irresoluble)
4
incongruous(adjective, absurd, intolerable, ungovernable)
4
insurmountable(adjective, unreasonable, useless, absurd, unruly)
4
irrational(adjective, absurd, number)
4
outrageous(adjective, intolerable, ungovernable)
4
stupid(adjective, absurd)
4
undesirable(adjective, unpleasant, terrible, extreme, painful)
4
unendurable(adjective, pain, extreme, painful, insufferable)
4
unsupportable(adjective, pain, unbearable)
4
useless(adjective, complete, wild, unreasonable, absurd)
3
cureless(adjective, broken, unchangeable, terminal, incurable)
3
doubtful(adjective, extraordinary, unreasonable, amazing, dubious)
3
fanciful
3
far-fetched(adjective, extraordinary, amazing, unlikely, implausible)
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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>