ef·​fi·​ca·​cious | \ˌe-fə-ˈkā-shəs \

Definition of efficacious 

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

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Other Words from efficacious

efficaciously adverb
efficaciousness noun

Choose the Right Synonym for efficacious

effective, effectual, efficient, efficacious mean producing or capable of producing a result. effective stresses the actual production of or the power to produce an effect. an effective rebuttal effectual suggests the accomplishment of a desired result especially as viewed after the fact. the measures to stop the pilfering proved effectual efficient suggests an acting or a potential for action or use in such a way as to avoid loss or waste of energy in effecting, producing, or functioning. an efficient small car efficacious suggests possession of a special quality or virtue that gives effective power. a detergent that is efficacious in removing grease

Examples of efficacious in a Sentence

taking a cookie break while studying is one of the most efficacious ways of rejuvenating the mind that I have ever discovered

Recent Examples on the Web

Sephora: The cosmetics mecca is offering a sweet deal on their affordably priced but super efficacious in-house line, Sephora Collection. Rachel Jacoby Zoldan, Glamour, "The Best Memorial Day 2018 Beauty Sales to Shop This Weekend," 23 May 2018 If strength and conditioning coaches, personal trainers, or physical therapists are armed with this type of information, then the most effective exercise selection and efficacious use of precious time with the athlete could be maximized. NOLA.com, "Optimum Performance: Targeting hip biomechanics to enhance Serena's performance," 6 Apr. 2018 The efficacious, enduring photographer has published a number of retrospective books that not only present a history of our time but offer a record for herself TIME.com, "Annie Leibovitz on Stephen Hawking," 26 Oct. 2017 And with the leeway Graham-Cassidy’s New Federalist framework would afford them, states might be able to find more efficacious ways to protect those people. Theodore Kupfer, National Review, "Jimmy Kimmel, Policy-Wonk Wannabe," 20 Sep. 2017 Kiehl's began as a neighborhood apothecary that always put its patrons first, so ensuring that Kiehl’s current fans have accessibility to our efficacious products in any neighborhood is important. Sarah Kinonen, Allure, "Kiehl's Is Coming to Sephora Stores," 28 July 2017 There remain many open questions in the field—how, why, and in what circumstances cognitive training is efficacious—and so painting in such broad strokes potentially undermines this important, ongoing research area. Beth Mole, Ars Technica, "Study: Lumosity boosts brain function as much as normal video games—by 0%," 10 July 2017 If the pilot program proves efficacious, it would be expanded within Colorado’s 18,000-inmate population and perhaps across the nation. The Denver Post Editorial Board, The Denver Post, "Tablet computers could prove valuable in helping reform inmates," 15 May 2017 This kind of brain-science has already proven efficacious: a preliminary study of humans working with help from machinated neuron tapping showed a six-fold increase in efficiency. Noah Shachtman, WIRED, "Darpa Wants Brainy Machines to Replace Bored G.I.s," 16 Apr. 2009

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'efficacious.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of efficacious

1528, in the meaning defined above

History and Etymology for efficacious

Latin efficac-, efficax, from efficere

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The first known use of efficacious was in 1528

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English Language Learners Definition of efficacious

: having the power to produce a desired result or effect

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Comments on efficacious

What made you want to look up efficacious? Please tell us where you read or heard it (including the quote, if possible).


something that serves to warn or remind

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