What "screwball" means in baseball

In baseball, a screwball is a type of pitch thrown by a pitcher. It is a breaking ball that moves in the opposite direction to a curveball. A left-handed pitcher would throw a screwball that moves down and in towards the hitter, while a right-handed pitcher would throw a screwball that moves down and away from the hitter. It is a difficult pitch to master and is not commonly used in baseball today.