12
impossible(adjective, improper)
12
unsustainable
8
impractical(adjective, improper, impossible)
6
unfeasible(adjective, improper, impossible, feasible)
6
inconceivable(adjective, improper, impossible)
5
unlikely(adjective, improper, impossible)
4
unworkable(adjective, improper, impossible)
3
unreasonable(adjective, improper, impossible)
3
sentimental
2
hopeless
2
fantastic
2
implausible(adjective, improper, impossible)
2
impracticable
2
unattainable(adjective, improper, impossible)
2
unpractical(adjective, improper, impossible)
1
disadvantageous(adjective, improper, impossible)
1
futile
1
improbable
1
improper(adjective, impossible)
1
inappropriate(adjective, improper, impossible)
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APASmart Define. (2015). feasible thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/feasible/thesaurus/antonyms
ChicagoSmart Define. 2015. "feasible thesaurus" https://smartdefine.org/feasible/thesaurus/antonyms (accessed September 26, 2026).
HarvardSmart Define 2015, feasible thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/feasible/thesaurus/antonyms>.
MLASmart Define. "feasible thesaurus" 13 April 2015. Web. 26 September 2026. <https://smartdefine.org/feasible/thesaurus/antonyms>