5
specious(adjective, correct, wrong, fake, false)
5
valetudinarian(noun, adjective, disease)
5
weakly(adverb, enervated, senescent, irresilient)
4
contradictory(adjective, absurd, irrational, arbitrary, perverse)
4
defunct(adjective, functioning, extinct)
4
handicap
4
imperfect(adjective, mean, weak, down, ill)
4
impotent(adjective, weak, poor, inadequate, feeble)
4
incompetent(adjective, poor, inadequate, useless, unfit)
4
inconsequent
4
ineffectual(adjective, poor, inadequate, unsound, trifling)
4
inexact(adjective, wrong, fake, false, counterfeit)
4
inferior(adjective, bad)
4
poorly(adjective, adverb, mean, weak, sick)
4
reasonless(adjective, foolish, unreasonable, irrational, worthless)
4
run-down(adjective, sick, unhealthy, unfit, infirm)
4
sick person(noun, expression, idiom, case, subject)
4
unavailing
4
unfavorable(adjective, bad)
4
unfounded(adjective, wrong, fake, false, counterfeit)
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APASmart Define. (2016). invalid thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/invalid/thesaurus/synonyms
ChicagoSmart Define. 2016. "invalid thesaurus" https://smartdefine.org/invalid/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2016, invalid thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/invalid/thesaurus/synonyms>.
MLASmart Define. "invalid thesaurus" 29 March 2016. Web. 20 September 2026. <https://smartdefine.org/invalid/thesaurus/synonyms>