Efficacious and Weak

Opposite meaning words

Efficacious adjective - Producing or capable of producing a desired result.

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Weak is an antonym for efficacious in efficient topic.

Weak adjective - Lacking bodily strength.

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Efficacious is an antonym for weak.

Nearby Words: weaken, weakness, weakly, weakening, weakling

Cite this Source

Weak and Efficacious. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/efficacious/weak

Efficacious & Weak. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/efficacious/weak>.

Weak or Efficacious. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/efficacious/weak.

Google Ngram Viewer shows how "efficacious" and "weak" have occurred on timeline