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

Marlow’s testimony also challenged the efficacy of Flock cameras and argued that the only situations that they have been studied and found to deter crime is in relation to car thefts and property crimes. — Graham Hurley, CNN Money, 1 Nov. 2026

For years, Apple questioned the necessity and efficacy of laptop touch screens but worked on implementing the technology—both behind the scenes and in the open—through its iPhone and iPad product lines. — Joe Osborne, PC Magazine, 29 Oct. 2026

But the peptides covered in the latest HHS policy haven’t undergone the safety and efficacy testing required by the FDA to obtain approval for human use. — Emily Kay Votruba, EverydayHealth.com, 29 Oct. 2026

They can be synthesized such as medications like insulin and GLP-1 drugs, which have both been FDA approved for safety and efficacy following clinical trials. — ABC News, 28 Oct. 2026