Efficacious and Inefficacious

Opposite meaning words

Efficacious adjective - Marked by qualities giving the power to produce an intended effect.

Usage example: "written propaganda is less efficacious than the habits and prejudices...of the readers"-Aldous Huxley

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Inefficacious is an antonym for efficacious in topics: effective, efficient.

Inefficacious adjective - Not producing the desired result.

Usage example: his efforts to restore the neglected houseplant back to health were belated and sadly inefficacious

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Efficacious is an antonym for inefficacious.

Cite this Source

Inefficacious and Efficacious. (2016). Retrieved 2026, August 16, from https://thesaurus.plus/related/efficacious/inefficacious

Efficacious & Inefficacious. N.p., 2016. Web. 16 Aug. 2026. <https://thesaurus.plus/related/efficacious/inefficacious>.

Inefficacious or Efficacious. 2016. Accessed August 16, 2026. https://thesaurus.plus/related/efficacious/inefficacious.

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