Wordorigins.org

One of the etymologies that is frequently debated in bars and other public gathering places is that of card shark v. card sharp. The question is which is the original. Both terms mean someone skilled in cheating at cards, but card sharp is the older of the two, appearing in Bret Harte’s 1884 On The Frontier:

We ain’t takin’ this step to make a card sharp out of him.