Synonyms|412Antonyms|83|Broader|4Narrower|1Related|376

33 entries under adjective topic. ×

5
incapable
5
inefficacious
4
ineffective
4
inefficient
4
unproductive
3
unqualified
3
unsuccessful
3
useless
2
ineffectual
1
awkward
1
bungling
1
clumsy
1
defective
1
deficient
1
faulty
1
flimsy
1
impotent
1
incompetent
1
inexpert
1
lazy
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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>