(formal)(typically of something inanimate or abstract) successful in producing a desired or intended result; effective (正式)(尤指无生命或抽象事物)有效的,灵验的 this treatment was efficacious in some cases. 该疗法有时有效。
派生 efficaciously adverb efficaciousness noun 语源
early 16th cent.: from Latin efficax, efficac- (from efficere 'accomplish': see effect) + -ious