efficacy

/EF-ih-kuh-see/noun

the ability to produce a desired result

The trial measures the vaccine's efficacy over two years.
Synonyms
effectiveness, potency, success
Antonyms
ineffectiveness
Memory hook
efficax: force that finishes the job.

Learn efficacy and 1,000+ GRE words with spaced repetition and an AI tutor.

Start learning free