Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.

EXAMPLES FROM THE WEB FOR EFFICACY

Much has been said concerning the efficacy of the Water Fly as a lure.

A few tears mingled with the draught, and perhaps gave it all its efficacy.

He no more believes in the efficacy of soap than in the efficacy of a good reputation.

All races have uttered this prayer, apparently with a firm belief in its efficacy.

Day by day her faith in the efficacy of her petitions had grown upon her.

This he readily accepted, trusting to the efficacy of the antidote.

This proved fortunate, for the better testing of the efficacy of the system.

Did he ever offer you the support of his vows, or did he ever praise the efficacy of his holiness?

The oak, for instance, has not the efficacy of the fir, nor the cypress that of the elm.

He himself had had occasion enough to note the efficacy of that vehicle.

WORD ORIGIN

1520s, from Latin efficacia "efficacy, efficiency," from efficax (genitive efficacis) "powerful, effective," from stem of efficere "work out, accomplish" (see effect). Earlier in same sense was efficace (c.1200), from Old French eficace (14c.), from Latin efficacia; also efficacite (early 15c.), from Latin efficacitatem.

MORE RELATED WORDS FOR EFFICACY

Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.