Its super-efficient cells eagerly gulped the rich radioactive substances.
But now look what the firm is turning out under Trenton Lauren, old Bill's super-efficient son!
Mrs. Horace A. Gower rather prided herself on the noiseless, super-efficient operation of her domestic machinery.
"capable of producing the desired effect," late 14c., "making, producing immediate effect," from Old French efficient and directly from Latin efficientem (nominative efficiens) "effective, efficient, producing, active," present participle of efficere "work out, accomplish" (see effect). Meaning "productive, skilled" is from 1787. Related: Efficiently.