efficaciousness efficaciously • efficacity · · · Info · Definitions · Synonyms · Characters · · efficaciousness · · Text Latin · · Script 15 · · Length Definitions · · · (noun) capacity or power to produce a desired effect. Synonyms: efficacy. Example: "Concern about the safety and efficacy of the vaccine." · · Noun Definition 1 Synonyms · · · efficacy · · Synonym 1 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 f latin small letter f U+0066 i latin small letter i U+0069 n latin small letter n U+006E o latin small letter o U+006F s latin small letter s U+0073 u latin small letter u U+0075