efficacious

[ef-i-key-shuh s]

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.

Origin of efficacious

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

Related formsef·fi·ca·cious·ly, adverbef·fi·ca·cious·ness, nounnon·ef·fi·ca·cious, adjectivenon·ef·fi·ca·cious·ly, adverbun·ef·fi·ca·cious, adjectiveun·ef·fi·ca·cious·ly, adverb

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for efficacious

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

Examples from the Web for efficacious

Contemporary Examples of efficacious

I asked him if he thought cattle cars would be an efficacious means of transporting the Palestinians to their new homes.
The Wildest Moments From CPAC
Max Blumenthal
March 2, 2009

Historical Examples of efficacious

And some of the most efficacious burrowers have been their own spiritual children.
A Writer's Recollections (In Two Volumes), Volume I
Mrs. Humphry Ward
Everyday influences, even the smallest and most dissimulated, are often the most efficacious.
The Sexual Question
August Forel
Relics have served as efficacious instruments to accomplish that end.
Roman Catholicism in Spain
Anonymous
Whatever the brew might be worth, the whisky certainly was efficacious.
The Heart of Thunder Mountain
Edfrid A. Bingham
Efficacious as this mode of execution may seem, it was neither speedy nor merciful.
Fox's Book of Martyrs
John Foxe

British Dictionary definitions for efficacious

efficacious

adjective

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

Derived Formsefficaciously, 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

Word Origin and History for efficacious

adj.

"sure to have the desired effect" (often of medicines), 1520s, from Latin efficaci-, stem of efficax (see efficacy) + -ous. Related: Efficaciously; efficaciousness.