efficient

efficient (http://definr.com/efficient)

     adj 1: being effective without wasting time or effort or expense;
            "an efficient production manager"; "efficient engines
            save gas" [ant: inefficient]
     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" [syn:
        effective]