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 My company makes money when a third party provider recommends efficacious treatments of root cause non-pharmaceutical interventions. Miles Bryan, Vox, 30 Jan. 2025 Not all experts agree on whether eye creams are any more efficacious than, say, regular creams. Jenny Berg, Vogue, 5 Jan. 2025 Studies have shown navel administration of medication is efficacious and that navel oiling can help with digestion, as well as potentially relieve gynecological discomfort. Margaux Anbouba, Vogue, 18 Dec. 2024 Research suggests that the use of antiretroviral drugs and advances in managing HIV infections have helped make solid organ transplants in people with HIV safer and more efficacious. Jacqueline Howard, CNN, 27 Nov. 2024 See All Example Sentences for efficacious
Recent Examples of Synonyms for efficacious
Adjective
  • Public services, from healthcare to transportation, adapt in real time using machine learning, creating a city that is not just efficient but truly responsive to its residents.
    Cathy Hackl, Forbes, 23 Mar. 2025
  • The risk in his game gets neutralized when he’s given a defensive assignment, and the result is a more efficient, trustworthy player.
    Arpon Basu, The Athletic, 23 Mar. 2025
Adjective
  • The North Carolina Forest Service has issued a statewide ban on all open burning and has cancelled all burning permits effective from 8 a.m. Friday until further notice.
    NC Weather Bot, Charlotte Observer, 22 Mar. 2025
  • Getting treatment For women experiencing pelvic floor muscle tension, pelvic floor physical therapy is often an effective treatment option to reduce pain and prevent muscles from becoming overly tight in the future, Falter said.
    Julianna Bragg, CNN, 22 Mar. 2025
Adjective
  • However, the most potent M&A storytelling combines all three.
    Valerie Chan, Forbes, 21 Mar. 2025
  • Benzene on the other hand is a highly potent carcinogen and is dangerous through ingestion, skin absorption inhalation and injection.
    Thomas G. Moukawsher, Newsweek, 21 Mar. 2025

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Cite this Entry

“Efficacious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/efficacious. Accessed 2 Apr. 2025.

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