Synonyms|412Antonyms|83|Broader|4Narrower|1Related|376
1
uneffective
1
unprofitable
1
vain
0
empty
0
dependent(adjective, strong, power, valid, legal)
0
halfhearted
0
hamstrung
0
hollow
0
hopeless
0
idle
0
inadequate
0
inappropriate
0
inapt
0
incomplete
0
inept
0
inexpedient
0
inexperienced
0
inoperative
0
insufficient
0
lame
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APASmart Define. (2015). efficacious thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/efficacious/thesaurus/antonyms
ChicagoSmart Define. 2015. "efficacious thesaurus" https://smartdefine.org/efficacious/thesaurus/antonyms (accessed September 23, 2026).
HarvardSmart Define 2015, efficacious thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/efficacious/thesaurus/antonyms>.
MLASmart Define. "efficacious thesaurus" 13 October 2015. Web. 23 September 2026. <https://smartdefine.org/efficacious/thesaurus/antonyms>