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
And an even more powerful next generation of medicines is quickly approaching, churning out trial results – including some new ones Thursday – that leave current options in the dust in terms of efficacy.
—
Meg Tirrell, CNN Money, 19 Mar. 2026
The best Korean sunscreens were arguably the gateway to K-beauty, though while Korean skincare has become commonplace, that doesn’t diminish SPF’s efficacy.
—Deanna Pai, Vogue, 19 Mar. 2026
No crunch, greasy residue, or flakes here—just pure efficacy.
—Catharine Malzahn, Glamour, 18 Mar. 2026
According to the team, these experiments support the efficacy of Indigenous medicinal practices, and also reinforce the possibility that Neanderthals used birch tar to treat their own wounds.
—Laura Baisas, Popular Science, 18 Mar. 2026
See All Example Sentences for efficacy
Meg Tirrell, CNN Money, 19 Mar. 2026
The best Korean sunscreens were arguably the gateway to K-beauty, though while Korean skincare has become commonplace, that doesn’t diminish SPF’s efficacy.
—Deanna Pai, Vogue, 19 Mar. 2026
No crunch, greasy residue, or flakes here—just pure efficacy.
—Catharine Malzahn, Glamour, 18 Mar. 2026
According to the team, these experiments support the efficacy of Indigenous medicinal practices, and also reinforce the possibility that Neanderthals used birch tar to treat their own wounds.
—Laura Baisas, Popular Science, 18 Mar. 2026
See All Example Sentences for efficacy
Recent Examples of Synonyms for efficacy
Noun
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The bill proposes creating a comparative effectiveness review process for prescription drugs on the Medicaid formulary.—
James Hart,
Hartford Courant,
30 Mar. 2026
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No injuries were reported among passengers or crew, underscoring the effectiveness of both onboard procedures and ground coordination.—
Aamir Khollam,
Interesting Engineering,
30 Mar. 2026
Noun
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With its PrecisionCore Heat-Free technology, the ink dries quickly to avoid smudging, while the two-sided printing capabilities increase efficiency.—
George Yang,
PC Magazine,
28 Mar. 2026
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But the transition from accumulation to preservation introduces a different kind of calculus — one where tax efficiency can matter as much as market returns.—
Allison Palmer,
Fort Worth Star-Telegram,
27 Mar. 2026
Cite this Entry
“Efficacy.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/efficacy. Accessed 1 Apr. 2026.
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