screwball

A pitched ball that curves in the direction opposite to that of a normal curve ball.

An eccentric, impulsively whimsical, or irrational person.

Impulsively whimsical; eccentric.

A pitch thrown with added pressure by the index finger and a twisting wrist motion resulting in a motion to the right when thrown by a right-handed pitcher.

One who behaves in a crazy manner.

Crazy, offbeat, bizarre, zany, or weird.

a whimsically eccentric person

foolish; totally unsound

a pitch with reverse spin that curves toward the side of the plate from which it was thrown