Efficacy and Effectivity

Efficacy

Efficacy noun - Capacity or power to produce a desired effect.
Usage example: concern about the safety and efficacy of the vaccine

Effectivity and efficacy are semantically related in effectiveness topic. In some cases you can use "Effectivity" instead a noun "Efficacy", when it comes to topics like efficiency.

Effectivity

Effectivity noun - Power to be effective; the quality of being able to bring about an effect.
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Synonyms for Effectivity

Efficacy and effectivity are semantically related in effectiveness topic. You can use "Efficacy" instead a noun "Effectivity", if it concerns topics such as efficiency.
Cite this Source
Effectivity and Efficacy. (2016). Retrieved 2026, August 02, from https://thesaurus.plus/related/efficacy/effectivity
Efficacy & Effectivity. N.p., 2016. Web. 02 Aug. 2026. <https://thesaurus.plus/related/efficacy/effectivity>.
Effectivity or Efficacy. 2016. Accessed August 02, 2026. https://thesaurus.plus/related/efficacy/effectivity.
Google Ngram Viewer shows how "efficacy" and "effectivity" have occurred on timeline