A person or thing that spits. The spitter in the crowd was quickly removed by security.
A person who habitually spits tobacco juice. The old cowboy was known as a spitter, always with a wad of tobacco in his cheek.
A baseball pitch (spitball) on which the ball has been doctored with saliva or another substance to affect its flight. The umpire suspected the veteran hurler of throwing a spitter in the late innings.