1. (a.) Productive; adept; characterized by energetic and useful activity\; as, an efficient officer, power.

2. (n.) An efficient cause; a prime mover.

able active adequate au fait banausic capable competent economic effective effectual efficacious equal to feasible fit fitted fitted for functional go journeyman operable operational operative practicable practical pragmatic productive proficient qualified realizable suited thrifty unwasteful up to up to snuff well-fitted well-qualified well-suited workable worthy