Synonym Chooser

How does the adjective efficacious contrast with its synonyms?

Some common synonyms of efficacious are effective, effectual, and efficient. While all these words mean "producing or capable of producing a result," efficacious suggests possession of a special quality or virtue that gives effective power.

a detergent that is efficacious in removing grease

When is effective a more appropriate choice than efficacious?

In some situations, the words effective and efficacious are roughly equivalent. However, effective stresses the actual production of or the power to produce an effect.

an effective rebuttal

When would effectual be a good substitute for efficacious?

Although the words effectual and efficacious have much in common, effectual suggests the accomplishment of a desired result especially as viewed after the fact.

the measures to stop the pilfering proved effectual

When can efficient be used instead of efficacious?

While the synonyms efficient and efficacious are close in meaning, 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

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of efficacious Appealing to such a wide demographic is quite unique, and might speak to why the brand resonates: an intentional focus on effortless and efficacious beauty, which is something many women look for regardless of their age. Clara Ludmir, Forbes.com, 14 Aug. 2025 French beauty lovers might already be familiar with Typology, one of the leading brands for simple, efficacious formulas. Iman Balagam, Vogue, 11 July 2025 Rhode is dedicated to making products based in science and great formulation, simplifying many of the mysteries and complex narratives behind efficacious skincare. Jason Pham, StyleCaster, 29 May 2025 On the other side are patients living with untreated diseases hoping that pharmaceutical companies will soon develop an efficacious treatment. Wayne Winegarden, Forbes, 5 Mar. 2025 See All Example Sentences for efficacious
Recent Examples of Synonyms for efficacious
Adjective
  • And there are lots of other authorities that can be used—not as efficient, not as powerful.
    Suzanne Blake, MSNBC Newsweek, 2 Sep. 2025
  • Beck had an efficient first game in a Miami uniform, going 20-of-31 for 205 yards and two touchdown passes with zero interceptions.
    Scott Thompson, FOXNews.com, 1 Sep. 2025
Adjective
  • How To Clean Linoleum Floors With Vinegar Vinegar is effective at cleaning floors and disinfecting them, but for more cleaning power, add a few squirts of dish soap to the mix, which works well at removing grease and grime from floors.
    Daley Quinn, Southern Living, 7 Sep. 2025
  • Alpine remains in a significant state of rebuild under Briatore, its effective boss.
    Madeline Coleman, New York Times, 6 Sep. 2025
Adjective
  • Arquila will spearhead an always-potent running game, which could include versatile senior Jack Bucar, junior Gavin Stone and sophomores Logan Lennon and Kelen Wilson.
    Steve Reaven, Chicago Tribune, 28 Aug. 2025
  • The weed making its way from hand-to-hand is potent.
    Josh Crutchmer, Rolling Stone, 28 Aug. 2025

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Cite this Entry

“Efficacious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/efficacious. Accessed 9 Sep. 2025.

More from Merriam-Webster on efficacious

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