12
feeble(adjective, strong, fit, ineffective)
12
unhealthy(adjective, sick)
11
ill(adjective, sick)
9
insane(adjective, sound, sensible, foolish, ill)
9
paranoid
7
harmful(adjective, good, harmless)
6
allergic
6
noxious(adjective, sweet, injurious, deadly)
5
infirm(adjective, weak, sound, sick)
5
damaging
5
fragile(adjective, strong)
5
poorly
5
trippy
4
sick(adjective, healthy, well)
4
ailing
4
baneful
4
deleterious
4
delicate(adjective, strong, hard, harsh, sickly)
4
frail(strong, sound)
4
gangrenous
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APASmart Define. (2016). healthy thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/healthy/thesaurus/antonyms
ChicagoSmart Define. 2016. "healthy thesaurus" https://smartdefine.org/healthy/thesaurus/antonyms (accessed September 24, 2026).
HarvardSmart Define 2016, healthy thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/healthy/thesaurus/antonyms>.
MLASmart Define. "healthy thesaurus" 24 March 2016. Web. 24 September 2026. <https://smartdefine.org/healthy/thesaurus/antonyms>