Main Entry: ef·fi·ca·cious

Pronunciation: \ˌe-fə-ˈkā-shəs\

Function: adjective

Etymology: Latin efficac-, efficax, from efficere

Date: 1528

: having the power to produce a desired effect <an efficacious remedy>

synonyms see effective

— ef·fi·ca·cious·ly adverb

— ef·fi·ca·cious·ness noun