definitions

efficacious

[ ef-i-key-shuh s ]
/ ˌɛf ɪˈkeɪ ʃəs /
|
SEE MORE SYNONYMS FOR efficacious ON THESAURUS.COM

adjective

capable of having the desired result or effect; effective as a means, measure, remedy, etc.: The medicine is efficacious in stopping a cough.

RELATED WORDS

effectual, effective, active, adequate, capable, competent, energetic, influential, operative, potent, powerful, serviceable, strong, successful, useful, virtuous, puissant

Nearby words

effervesce, effervescence, effervescent, effervescent salt, effete, efficacious, efficacity, efficacy, efficiency, efficiency apartment, efficiency expert

Origin of efficacious

1520–30; < Latin efficāci- (stem of efficāx) effectual. See efficient, -acious

Related forms

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for efficacious

British Dictionary definitions for efficacious

efficacious

/ (ˌɛfɪˈkeɪʃəs) /

adjective

capable of or successful in producing an intended result; effective as a means, remedy, etc

Derived Forms

efficaciously, adverbefficaciousness, noun

Word Origin for efficacious

C16: from Latin efficāx powerful, efficient, from efficere to achieve; see effect
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012