Source : Webster's Revised Unabridged Dictionary (1913)

Tosser \Toss"er\, n.
   Ohe who tosser. --J. Fletcher.

Source : WordNet®

tosser
     n 1: terms of abuse for a masturbator [syn: {jerk-off}, {wanker}]
     2: someone who throws lightly (as with the palm upward)