Efficacious and Vain
Opposite meaning words
Efficacious
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
Vain is an antonym for efficacious.
Vain
Vain adjective - Producing no results.
Usage example: all their efforts to escape proved vain
Efficacious is an antonym for vain.
Cite this Source
Vain and Efficacious. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/efficacious/vain
Efficacious & Vain. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/efficacious/vain>.
Vain or Efficacious. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/efficacious/vain.
Google Ngram Viewer shows how "efficacious" and "vain" have occurred on timeline