17 entries under obscure topic. ×

15
illogical(adjective, sense)
15
irrational(adjective, sound, rational, senseless)
12
unreasonable(adjective, correct, right, illogical)
9
unsound(adjective, illogical)
4
foolish(adjective, sound, wise, illogical)
2
improbable(adjective, illogical)
2
invalid(adjective, sound, reasonable, illogical)
2
unlikely(adjective, illogical)
1
implausible(adjective, illogical)
1
stupid(adjective, illogical)
1
unclear(adjective, illogical)
1
unintelligent(adjective, illogical)
1
unwise(adjective, illogical)
0
optional(adjective, illogical)
0
unrealistic(adjective, illogical)
0
unsuitable(adjective, illogical)
0
vague(adjective, illogical)
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APASmart Define. (2015). logical thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/logical/thesaurus/antonyms
ChicagoSmart Define. 2015. "logical thesaurus" https://smartdefine.org/logical/thesaurus/antonyms (accessed September 27, 2026).
HarvardSmart Define 2015, logical thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/logical/thesaurus/antonyms>.
MLASmart Define. "logical thesaurus" 19 October 2015. Web. 27 September 2026. <https://smartdefine.org/logical/thesaurus/antonyms>