screwball

Short definition from Wiktionary

Noun

1. 1
   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.
2. 2
   One who behaves in a crazy manner.
3. 3
   A screwball comedy.

Adjective

1. 1
   Crazy, offbeat, bizarre, zany, or weird.