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 Despite Chief Justice Warren formally writing the opinion to apply exclusively to education, its attack on segregation has—paradoxically—been most efficacious beyond that original context. Justin Driver, The Atlantic, 15 Mar. 2025 Providing the opportunity to cover these costs is essential for incentivizing continued medical innovation – helping patients still waiting for efficacious treatments. Wayne Winegarden, Forbes, 5 Mar. 2025 But the European Union’s post-national foreign policy is clearly more efficacious in some areas than in others. Kathleen R. McNamara, Foreign Affairs, 4 Mar. 2014 My company makes money when a third party provider recommends efficacious treatments of root cause non-pharmaceutical interventions. Miles Bryan, Vox, 30 Jan. 2025 See All Example Sentences for efficacious
Recent Examples of Synonyms for efficacious
Adjective
  • This Duke team is the second-most efficient the sport has seen since Ken Pomeroy started tracking efficiency in the 1996-97 season.
    Joe Rexrode, New York Times, 6 Apr. 2025
  • Illinois residents deserve a more efficient and effective governmental system than the current chaotic mix of unaccountable jurisdictions.
    David Greising, Chicago Tribune, 6 Apr. 2025
Adjective
  • Chemical control: Pesticides must make direct contact with the adult insect to be effective, and thrips are protected within the buds and plant tissues.
    Rita Perwich, San Diego Union-Tribune, 5 Apr. 2025
  • With the repeal of GPO, known as Government Pension Offset, which was passed at the end of 2024, which is retroactively effective as of January 2024, your survivor benefit is no longer reduced by two-thirds.
    Elliot Raphaelson, The Orlando Sentinel, 5 Apr. 2025
Adjective
  • To the contrary: Adding J.T. Miller was supposed to make the power play more potent.
    Arthur Staple, New York Times, 3 Apr. 2025
  • The Handmaid’s Tale is still more than capable of nightmarish images and emotionally potent sequences.
    Daniel Fienberg, HollywoodReporter, 3 Apr. 2025

Browse Nearby Words

Podcast

Cite this Entry

“Efficacious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/efficacious. Accessed 16 Apr. 2025.

More from Merriam-Webster on efficacious

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!