INEFFICACIOUS Synonyms: 72 Similar and Opposite Words

inefficacious

adjective

(ˌ)i-ˌne-fə-ˈkā-shəs

Definition of inefficacious

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

as in futile

producing no results an inefficacious medication for a rare form of tuberculosis

Synonyms & Similar Words

Antonyms & Near Antonyms

Example Sentences

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Recent Examples of inefficacious 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

As the unsuccessful regime-change effort in Iran demonstrated, there are no shortcuts to besting the axis countries, together or individually.

— Andrea Kendall-Taylor, Foreign Affairs, 16 Oct. 2026
Von Dohlen, a financial adviser and conservative activist who has run three unsuccessful campaigns for City Council, was unopposed in the Republican primary.

— Katie Bartlett, San Antonio Express-News, 16 Oct. 2026

Definition of unsuccessful

Adjective

Adelaide’s music had become an argument, however futile, with finality.

— Yiyun Li, New Yorker, 13 Oct. 2026
Before the court fight was launched, Edwin Benn, the arbitrator who oversaw 2023 contract negotiations between the city and FOP, warned the City Council that any attempt to undermine his award to the union would be futile.

— Sam Charles, Chicago Tribune, 24 Sep. 2026

Definition of futile

Adjective

By any objective standard, that technology was outdated, labor-intensive, imprecise, and inefficient.

— Matt Alt, Fortune, 18 Oct. 2026
In February, the IMF separately warned that Beijing’s state subsidies were producing inefficient firms, with total subsidies amounting to some 4% of GDP.

— Brendan Ruberry, semafor.com, 13 Oct. 2026

Definition of inefficient

Adjective

Third-string quarterback Brock Thomas started the game for the Ducks but was largely ineffective, going 9 of 20 for 54 yards and an interception.

— ABC News, ABC News, 18 Oct. 2026
In the debate Thursday night, Sullivan highlighted his record defending Alaska's energy and military interests in the state and attacked Peltola as ineffective during her time in office.

— Matthew Choi The Washington Post, Arkansas Online, 17 Oct. 2026

Definition of ineffective

Adjective

The lesson is not to abandon the region but to rethink an approach that has become both too costly and counterproductive.

— Philip H. Gordon, Foreign Affairs, 12 Oct. 2026
Industry analysts note that abandoning the export ban reflects recognition that such restrictions could prove counterproductive.

— , CNBC, 7 Oct. 2026