11
unsustainable
5
unreasonable(adjective, good, wrong, fair)
5
undeserving
3
indefensible(adjective, inexcusable, excusable)
3
unjustifiable(adjective, wrong, unreasonable)
3
unwarranted(adjective, right, wrong, reasonable, unreasonable)
3
groundless
2
inexcusable(adjective, forgivable)
2
outrageous
2
illogical
2
insupportable
2
unacceptable(adjective, wrong, unreasonable)
1
excessive
1
gratuitous
1
illegitimate(adjective, good, wrong, unreasonable, legal)
1
invalid(adjective, wrong, unreasonable)
1
prohibited(adjective, wrong, unreasonable)
1
unforgivable
1
unfounded
1
unlawful(adjective, wrong, unreasonable)
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APASmart Define. (2016). justifiable thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/justifiable/thesaurus/antonyms
ChicagoSmart Define. 2016. "justifiable thesaurus" https://smartdefine.org/justifiable/thesaurus/antonyms (accessed September 23, 2026).
HarvardSmart Define 2016, justifiable thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/justifiable/thesaurus/antonyms>.
MLASmart Define. "justifiable thesaurus" 29 March 2016. Web. 23 September 2026. <https://smartdefine.org/justifiable/thesaurus/antonyms>