1. In a car with manual transmission, shifting gears before the recommended shift time.
2. In golf, to cut short the backswing in half, sometimes trading precision for a faster swing. It does not necessarily affect the distance the ball travels.
1. You see Gary over there? He says he's good with cars, but you can tell every time he shortshifts in his Skyline.
2. Think Tom is a nice guy? Every Sunday, he goes to the course and shortshifts his way to the group in front of him just to be a douche.