1
as in unsuccessful
not producing the desired result
his efforts to restore the neglected houseplant back to health were belated and sadly inefficacious
Synonyms & Similar Words
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Antonyms & Near Antonyms
2
as in futile
producing no results
an inefficacious medication for a rare form of tuberculosis
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Antonyms & Near Antonyms
Example Sentences
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Recent Examples of inefficacious
Most wore inefficacious cloth masks, too.
—
James Lileks, National Review, 25 Aug. 2022
Day — who grew up watching the spelling bee — came up with the concept of exploring the psyche of a winner with an ultimately inefficacious career in 2015 while at a UCB improv sketch-writing class.
—NBC News, 6 Oct. 2020
Recent Examples of Synonyms for inefficacious
Adjective
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But her appeal was unsuccessful.—
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Industry lobbying unsuccessful to date Some advocates for the restaurant industry have been lobbying to change the way service fees are treated.—
Adjective
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But the rally felt less threatening than futile.—
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And this is asking that question, how are these people finding meaning and purpose in their lives that feel so oppressive and futile?—
Adjective
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Willingly taking back an inefficient contract from a contender, even if that contract has term involved, is just a more extreme application of this basic logic.—
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In processes like this, any loss of carbon as carbon dioxide is a key sign that the underlying process is inefficient.—
Adjective
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Brown’s statement on Monday was mostly useless corporate-speak.—
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This tiny amount of copper acts as a molecular steering wheel, preventing sugar molecules from shattering into useless carbon dioxide.—
Adjective
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The suspect then allegedly stepped towards the officers with the weapon, and officers deployed a Taser and a firearm at the same time, but the Taser was ineffective.—
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Combined with sensational media coverage and advocacy by special interests, such studies have led to ineffective or even harmful national health policies.—
Adjective
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Even Bill Gates, a onetime stalwart champion of climate action, said this week that near-term emissions targets are a distraction at best and could even be counterproductive for human welfare.—
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What resulted is one of the most comic, counterproductive, and clumsy episodes in the long history of British efforts to deal with Ireland.—
Cite this Entry
“Inefficacious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/inefficacious. Accessed 13 Jan. 2026.
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