efficient

英 [ɪ'fɪʃ(ə)nt] 美[ɪ'fɪʃnt]

1. being effective without wasting time or effort or expense;: "an efficient production manager"; "efficient engines save gas"

2. able to accomplish a purpose; functioning effectively;: "people who will do nothing unless they get something out of it for themselves are often highly effective persons..."-G.B.Shaw; "effective personnel"; "an efficient secretary"; "the efficient cause of the revolution"