In baseball, when a pitcher throws a curveball, it breaks to a right-handers left and a left-handers right.
Early in the twentieth century, the great Christy Mathewson came up with a pitch that broke in the opposite direction and completely baffled opposing batters, who called it a “screwball.”
It became a word used to describe anything eccentric or totally surprising, including some humans.
Yes, people can be screwballs too.
