English dictionary

efficacy

/'/E/f/@/k/@/s/i/

Definitions, examples, synonyms and antonyms from WordNet 3.0.

noun

capacity or power to produce a desired effect

noun.attribute

Examples
Concern about the safety and efficacy of the vaccine.

Synonyms efficaciousness

Antonyms inefficaciousness inefficacy

Source: WordNet 3.0
Power to produce effects; operation or energy of an agent or force; production of the effect intended; as, the <i>efficacy</i> of medicine in counteracting disease; the <i>efficacy</i> of prayer.

noun

Source: webster1913