Did a few google searches on this, but not to my surprise, only results about video gaming come up.
In Hamlet, Reynaldo says: "As gaming, my lord." to which Polonius replies "Ay, or drinking, fencing, swearing, Quarreling, drabbing—you may go so far"
or to describe Germans, British lexicographer Sir William Smith writes: “Their men found their chief delight in the perils and excitement of war. In peace they passed their lives in listless indolence, only varied by deep gaming and excessive drinking.”
I'm guessing it means something along the lines of having fun, but is there a more specific definition that anyone knows?