Synonyms and Antonyms of efficacious
- taking a cookie break while studying is one of the most efficacious ways of rejuvenating the mind that I have ever discovered
hyperefficient, ultraefficient
accomplished, adept, consummate, experienced, expert, masterly, practiced (also practised), proficient, skilled, skillful, versed, veteran, virtuoso
cogent, convincing, killer, sound, striking, telling, valid
applicable, feasible, functional, practicable, practical, realizable, usable (also useable), workable