EFFICACIOUSNESS Synonyms: 22 Similar and Opposite Words

efficaciousness

noun

Definition of efficaciousness

as in efficacy

the power to produce a desired result the efficaciousness of exercise in improving physical as well as emotional well-being

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Recent Examples of Synonyms for efficaciousness

Noun

As Kennedy has spent years questioning vaccine efficacy before becoming HHS Secretary, this messaging from an extremely influential health leader may have also contributed to vaccine hesitancy and declining vaccination rates.

— Omer Awan, Forbes.com, 2 Aug. 2026
When the question is accumulated knowledge with years of safety and efficacy data, refined dosing, and better patient selection, sponsors are told that information doesn’t go the other way.

— Kat Bryant Knudson, STAT, 31 July 2026

Definition of efficacy

Noun

But research has been limited and is still in the early stages of understanding the full extent of their effectiveness, safety and long-term effects when used for addiction treatment.

— Steven Beynon, ABC News, 30 July 2026
His 55 per cent success rate was better than anyone in the top 75 for take-on attempts — a marker of his effectiveness from these situations.

— Anantaajith Raghuraman, New York Times, 30 July 2026

Definition of effectiveness

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efficacious

efficaciousness

efficacity

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“Efficaciousness.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/efficaciousness. Accessed 3 Aug. 2026.

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Synonyms of efficaciousness

noun

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