Definition of EFFICACY

efficacy

Plural: efficacies

Noun

  • capacity or power to produce a desired effect
    • "concern about the safety and efficacy of the vaccine"
  • The ability to produce a desired effect under ideal testing conditions.
  • A degree of ability to produce a desired effect; effectiveness.

Origin / Etymology

From Old French efficace, from Late Latin efficācia (“efficacy”), from efficāx (“efficacious”); see efficacious.

Antonyms

inefficacy

Scrabble Score: 21

efficacy is a valid Scrabble (US) TWL word
efficacy is a valid Scrabble Word in Merriam-Webster MW Dictionary
efficacy is a valid Scrabble Word in International Collins CSW Dictionary

Words With Friends Score: 22

efficacy is a valid Words With Friends word