Sentence:  Of the two , Porter is justly the better known , for he went far beyond the vital finding of fiction for films to take the first step toward fashioning a language of film , toward making the motion picture the intricate , <WSD>efficient</WSD> time machine that it has remained since , even in the most inept hands . 
Meaning of the word marked with <WSD> tags:  being effective without wasting time or effort or expense