Source : Webster's Revised Unabridged Dictionary (1913)

Welsher \Welsh"er\, n.
   One who cheats at a horse race; one who bets, without a
   chance of being able to pay; one who receives money to back
   certain horses and absconds with it. [Written also
   {welcher}.] [Slang, Eng.]

Source : WordNet®

welsher
     n : someone who swindles you by not repaying a debt or wager
         [syn: {welcher}]