Efficacious and Ineffectual

Opposite meaning words

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

Usage example: taking a cookie break while studying is one of the most efficacious ways of rejuvenating the mind that I have ever discovered

Show all Definitions

Ineffectual is an antonym for efficacious in effective topic.

Ineffectual adjective - Not producing the desired result.

Usage example: an ineffectual effort to find the trail again did at least lead them to another stunning view of the canyon

Show all Definitions

Efficacious is an antonym for ineffectual.

Nearby Words: ineffective, ineffectively

Cite this Source

Ineffectual and Efficacious. (2016). Retrieved 2026, July 22, from https://thesaurus.plus/related/efficacious/ineffectual

Efficacious & Ineffectual. N.p., 2016. Web. 22 Jul. 2026. <https://thesaurus.plus/related/efficacious/ineffectual>.

Ineffectual or Efficacious. 2016. Accessed July 22, 2026. https://thesaurus.plus/related/efficacious/ineffectual.

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