Synonyms of efficacy

efficacy

noun

ˈe-fi-kə-sē 

as in effectiveness

the power to produce a desired result

questioned the efficacy of the alarms in actually preventing auto theft

Synonyms & Similar Words

• effectiveness
• efficaciousness
• efficiency
• productiveness
• ability
• efficacity
• effectualness
• capability
• edge
• strength
• potency
• capacity
• puissance

Antonyms & Near Antonyms

• ineffectiveness
• inefficiency
• inability
• inadequacy
• ineffectuality
• ineffectualness
• incompetence
• incompetency
• inadequateness

Example Sentences

Recent Examples of efficacy

In early September, there was a virtual call with 80-plus artists, executives and stakeholders from the Asian music community with trustees and governors from the Recording Academy to review the efficacy of the new award. — Hannah Dailey, Billboard, 2 Oct. 2026

Antibody-drug conjugates, gene therapies, cell therapies and personalized medicines are creating new questions around dose, exposure, efficacy, safety and patient variability. — Mirjam Trame, Forbes.com, 2 Oct. 2026

For Liberty, that means stock holding, replenishment, product efficacy, customer loyalty and whether momentum extends beyond a single hero product. — Rhea Cartwright, Vogue, 2 Oct. 2026

With efficacy and affordability top of mind, Skin Union’s product boast ph-balancing, and filler-free formulas suitable for all skin types, and all under $30. — Kaleigh Werner, Footwear News, 1 Oct. 2026