18
labyrinthine(adjective, hard, difficulty, difficult, complex)
18
oppressive(adjective, hard, difficult, complex)
18
painful(adjective, hard, difficult, complex)
18
sensitive(adjective, hard, difficult, complex)
18
sticky(adjective, hard, difficult, complex)
18
tricky(adjective, hard, difficult, complex)
17
unworkable(adjective, wild, unreasonable, useless, absurd)
16
absurd(adjective, hard, difficult, wild, unreasonable)
15
preposterous(adjective, false, ridiculous, absurd, bizarre)
14
unfeasible(adjective, perfect, wild, unreasonable, useless)
13
unimaginable(adjective, extraordinary, unusual, strange, unreasonable)
13
incredible(adjective, extraordinary, strange, unreasonable, unbelievable)
13
ridiculous(adjective, silly, stupid, funny, absurd)
11
impractical(adjective, perfect, wild, unreasonable, useless)
11
improbable(adjective, extraordinary, wild, strange, unbelievable)
11
insufferable(adjective, pain, terrible, horrible, extreme)
11
unbelievable(adjective, hard, extraordinary, strange, unreasonable)
10
unattainable(adjective, wild, unreasonable, useless, absurd)
10
unacceptable(adjective, cold, terrible, away, outside)
9
unlikely(adjective, extraordinary, unusual, strange, unreasonable)
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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>