inefficacy

noun

in·​ef·​fi·​ca·​cy (ˌ)i-ˈne-fi-kə-sē How to pronounce inefficacy (audio)
Synonyms of inefficacynext
: lack of power to produce a desired effect

Examples of inefficacy in a Sentence

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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.
Columnist Tom Philp argued that her situation demonstrated the inefficacy of California’s mental health and CARE Court system, which cannot force participants into treatment. — Jennah Pendleton, Sacbee.com, 14 Oct. 2026 The impunity of the powerful was measured by the inefficacy of the outraged. — Joshua Rothman, New Yorker, 24 Feb. 2026 When on day five of his mayoralty Zohran Mamdani acknowledged the inefficacy of homeless sweeps and avowed to end them, street homeless adults, advocates, and attorneys rejoiced. — Deborah Berkman, New York Daily News, 24 Feb. 2026 And the broader issue is that despite all the evidence showing its inefficacy, TANF reform still hasn't happened. — Aisha Nyandoro, Forbes.com, 3 Feb. 2026 See All Example Sentences for inefficacy

Word History

Etymology

Late Latin inefficacia, from Latin inefficac-, inefficax inefficacious, from in- + efficac-, efficax efficacious

First Known Use

circa 1615, in the meaning defined above

Time Traveler
The first known use of inefficacy was circa 1615

Rhymes for inefficacy

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Browse Nearby Words

inefficacity
inefficacy
inefficiency
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Cite this Entry

“Inefficacy.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/inefficacy. Accessed 20 Oct. 2026.

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