efficacy definition : ability to produce a desired result. Check meanings, examples, usage tips, pronunciation, domains, and related words. Discover expressions like "self- efficacy ", "luminous efficacy ", "prove the efficacy ". Efficacy is the quality of being successful in producing an intended result or effect. Learn how to use this word in different contexts, synonyms, and related terms with Collins English Dictionary. EFFICACY definition : 1. the ability of something to produce the intended result: 2. how well a particular treatment or…. Learn more.
