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efficacy

[ ef-i-kuh-see ]
/ ˈɛf ɪ kə si /
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See synonyms for: efficacy / efficacies on Thesaurus.com
noun, plural ef·fi·ca·cies.
capacity for producing a desired result or effect; effectiveness: a remedy of great efficacy.
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Sometimes ef·fi·cac·i·ty [ef-i-kas-i-tee] /ˌɛf ɪˈkæs ɪ ti/ .

Origin of efficacy

First recorded in 1520–30; from Latin efficācia, equivalent to efficāc- “effective, effectual” + -ia noun suffix; see efficacious, -y3

OTHER WORDS FROM efficacy

non·ef·fi·ca·cy, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

Words related to efficacy

adequacy, competence, effectiveness, potency, virtue, ability, capability, capableness, capacity, effect, efficaciousness, energy, force, influence, performance, power, strength, success, sufficiency, use

How to use efficacy in a sentence

  • That these two are different will easily be clear to anyone who passes in review their respective efficacies.

    The Consolation of Philosophy|Boethius

  • In silence and secrecy thought has been working, and the benignant efficacies of concealment speak for themselves.

    Ku Klux Klan|J. C. Lester

British Dictionary definitions for efficacy

efficacy
/ (ˈɛfɪkəsɪ) /
noun
the quality of being successful in producing an intended result; effectiveness
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
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