efficacious

Effective; possessing efficacy.

Adjective

  1. Effective; possessing efficacy.
    • This medicine is efficacious.
    • For, that the ordure, which continually gathers on the skin, would ſoon ſtop the pores of it, if the ſweat were not furniſht with ſome efficacious diſſolvent to open and pierce them. - 1669 August 25, “[An Accompt of...
    • "I see," said he, with a smile, "that you, like myself, are trying the effect of this sweet evening for the headach. I have already found it very efficacious, and so, I think, have you,"—again smiling, as he noticed the...

    Synonyms: effective

    Antonyms: inefficacious

Origin

From Old French efficacieux, from Latin efficāx (“efficacious”) + -ous, from efficere (“to effect, to accomplish”); see effect.

Forms

more efficacious most efficacious

Related

effect effective effectivity effectual efficacity efficacy efficiency efficient

Derived

efficaciously efficaciousness nonefficacious subefficacious unefficacious