Source : Webster's Revised Unabridged Dictionary (1913)

Hitter \Hit"ter\, n.
   One who hits or strikes; as, a hard hitter.

Source : WordNet®

hitter
     n 1: (baseball) a ballplayer who is batting [syn: {batter}, {slugger},
           {batsman}]
     2: someone who hits; "a hard hitter"; "a fine striker of the
        ball"; "blacksmiths are good hitters" [syn: {striker}]