switch-hitter（n.）
by 1919 in baseball slang, "ambidextrous batter, one who bats right- or left-handed;" see switch (n.), used adjectivally, + hit (v.). It is attested by 1956 in the colloquial slang sense of "bisexual person." Related: Switch-hitting.
A natural left-hand hitter never experiments from the other side of the plate. A right-hand batter who finds he is a sucker for a right-hand pitcher's curve ball becomes a switch-hitter for self protection. [Al Demaree, "Southpaws Swear at Switch-Hitters," Corsicana (Texas) Daily Sun, Feb. 7, 1935]
该词起源时间：1919年