Source : WordNet®

screwball
     n 1: a whimsically eccentric person [syn: {crackpot}, {crank}, {nut},
           {nut case}, {nutcase}, {fruitcake}]
     2: a pitch with reverse spin that curves toward the side of the
        plate from which it was thrown

screwball
     adj : foolish; totally unsound; "an impractical solution"; "a
           crazy scheme"; "half-baked ideas"; "a screwball
           proposal without a prayer of working" [syn: {crazy}, {half-baked},
            {softheaded}]