The ratio of the energy delivered by a machine to the energy supplied for its operation.
The quality or condition of being potent.
The condition or fact of being insufficient or falling short:
An inefficient act, design, or procedure:
(Cinematography) An illusion produced by technical means (as in "special effect")
(Psychol.) An emotion or feeling attached to an idea, object, etc.
Find another word for efficacy. In this page you can discover 19 synonyms, antonyms, idiomatic expressions, and related words for efficacy, like: effectiveness, productiveness, ability, efficiency, advantage, potency, impotency, inefficacy, uselessness, weakness and failure.