One entry found for efficacy.

Entry Word: efficacy
Function: noun
Text: the power to produce a desired result <questioned the efficacy of the alarms in actually preventing auto theft>
Synonyms effectiveness, effectualness, efficaciousness, efficiency, productiveness
Related Words ability, capability, capacity; potency, strength
Near Antonyms inability, inadequacy, incompetence
Antonyms ineffectiveness, ineffectualness, inefficiency