card sharp 
(also card sharper)
noun
A person who cheats at cards in order to win money.In one corner of the room a card sharp was cheating a few men, and in another a long game of poker was going on....
- The two themes have been a constant in his movies, control going hand-in-hand with regret, from Jason Bourne to Will Hunting and Mike McDermott, the card sharp in Rounders.
- These interminable stretches of consequence-free juvenile mayhem were interspersed with occasional moments of interest, such as the charismatic card sharp.