gammon
A joke, trick; play, sport, merriment.
countable, uncountable
A victory in backgammon achieved when the opponent has not borne off a single stone.
countable, uncountable
Toward the end of the game Roger had not borne off a single stone belonging to Roseanna, and she scored a gammon. She could not hide the triumph in her eyes. “Perhaps you will play a better game if we play for something closer to your heart,” she suggested.
Backgammon (the game itself).
countable, rare, uncountable
We started about 7:00 drinking beers and playing gammon. Then after getting a little “loose” we went to a girls dorm.
Where it comes from
From Middle English gamenen, gamene, from Old English gamnian, gæmnian, gamenian (“to joke, play”), from Proto-West Germanic *gamanōn, from Proto-Germanic *gamanōną (“to play, have fun, joke”). Cognate with Middle High German gamenen (“to mock, make fun of”), Icelandic gamna (“to have fun”). More at game.
Adapted from the Wiktionary entry gammon (CC BY-SA 4.0).