as in effectiveness
the power to produce a desired result
questioned the efficacy of the alarms in actually preventing auto theft
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Recent Examples of efficacy
Plus, the brand has clinical claims to back up the efficacy: In an independent consumer testing panel shared by the brand, after two weeks of use, participants found that frizz was improved by 22%, moisture levels increased by nearly 71%, and scalp redness reduced nearly 26%.
—
Catharine Malzahn, Glamour, 24 June 2025
That perception is combined with less confidence in U.S. global engagement and the efficacy of military solutions.
—Jacob Ware, The Conversation, 12 June 2025
This is a big problem in terms of the Presidents efficacy as well as well as his administration.
—Hollie Silverman, MSNBC Newsweek, 9 June 2025
Safety and efficacy vary highly between products; look for those that are independently tested and verified.
—Sarah Anzlovar, Verywell Health, 9 June 2025
See All Example Sentences for efficacy
Catharine Malzahn, Glamour, 24 June 2025
That perception is combined with less confidence in U.S. global engagement and the efficacy of military solutions.
—Jacob Ware, The Conversation, 12 June 2025
This is a big problem in terms of the Presidents efficacy as well as well as his administration.
—Hollie Silverman, MSNBC Newsweek, 9 June 2025
Safety and efficacy vary highly between products; look for those that are independently tested and verified.
—Sarah Anzlovar, Verywell Health, 9 June 2025
See All Example Sentences for efficacy
Recent Examples of Synonyms for efficacy
efficiency
Noun
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At the same time, niche and local players who master efficiency and identity—like Dragonfly and Goodlyfe—can still carve out major wins.—
Javier Hasse,
Forbes.com,
26 June 2025
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Arredondo is not alone in that sentiment as the legal profession, like so many other industries, tries to balance the efficiency gains offered by AI with safety.—
Jeff John Roberts,
Fortune,
26 June 2025
Cite this Entry
“Efficacy.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/efficacy. Accessed 6 Jul. 2025.
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