September is Etymology Month (9)

gamble 1726 (implied in gambling), from a dialectal survival of M.E. gammlen, variant of gamenen "to play, jest, be merry," from O.E. gamenian "to play, joke, pun," from gamen. Or possibly gamble is from a derivative of gamel "to play games" (1590s), itself likely a frequentative from game. Originally regarded as a slang word. The intrusive -b- may be from confusion with gambol.