Inefficacious and Lacking

Inefficacious

Inefficacious adjective - Producing no results.
Usage example: an inefficacious medication for a rare form of tuberculosis

Lacking and inefficacious are semantically related. In some cases you can use "Lacking" instead an adjective "Inefficacious".

Lacking

Lacking adjective - Not coming up to an expected measure or meeting a particular need.

Inefficacious and lacking are semantically related. Sometimes you can use "Inefficacious" instead an adjective "Lacking".

Nearby Words: lack, lacked
Cite this Source
Lacking and Inefficacious. (2016). Retrieved 2026, August 14, from https://thesaurus.plus/related/inefficacious/lacking
Inefficacious & Lacking. N.p., 2016. Web. 14 Aug. 2026. <https://thesaurus.plus/related/inefficacious/lacking>.
Lacking or Inefficacious. 2016. Accessed August 14, 2026. https://thesaurus.plus/related/inefficacious/lacking.
Google Ngram Viewer shows how "inefficacious" and "lacking" have occurred on timeline