Synonyms|359Antonyms|67|Broader|1Narrower|0Related|355
2
groundless
2
illogical
2
unfounded
2
unsubstantiated
1
baseless
1
fallacious
1
illegitimate
1
inconsequent
1
inconsequential
1
irrational
1
nonrational
1
nonvalid
1
unjustified
1
unreasonable
1
unsound
1
unsubstantial(adjective, substance, undeniable)
1
unsupported
1
unwarranted
1
weak
0
absurd
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APASmart Define. (2016). well-founded thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/well-founded/thesaurus/antonyms
ChicagoSmart Define. 2016. "well-founded thesaurus" https://smartdefine.org/well-founded/thesaurus/antonyms (accessed September 26, 2026).
HarvardSmart Define 2016, well-founded thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/well-founded/thesaurus/antonyms>.
MLASmart Define. "well-founded thesaurus" 29 March 2016. Web. 26 September 2026. <https://smartdefine.org/well-founded/thesaurus/antonyms>