Synonyms|428Antonyms|78|Broader|9Narrower|13Related|102
5
inefficacy
3
failure
3
inefficiency
3
weakness
2
feebleness
2
inefficaciousness
1
impotence
1
inability
1
inadequacy
1
incompetence
1
ineffectuality
1
ineffectualness
1
stupidity
1
uselessness
0
ineffectiveness
0
awkwardness
0
chaperon
0
clumsiness
0
colonize
0
defectiveness
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APASmart Define. (2015). efficacy thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/efficacy/thesaurus/antonyms
ChicagoSmart Define. 2015. "efficacy thesaurus" https://smartdefine.org/efficacy/thesaurus/antonyms (accessed September 21, 2026).
HarvardSmart Define 2015, efficacy thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/efficacy/thesaurus/antonyms>.
MLASmart Define. "efficacy thesaurus" 10 April 2015. Web. 21 September 2026. <https://smartdefine.org/efficacy/thesaurus/antonyms>