verb

• (dialectal) To joke, kid around, play.
• (backgammon) To beat by a gammon (without the opponent bearing off a stone).

noun

• (dialectal) A joke, trick; play, sport, merriment.
• (backgammon) A victory in backgammon achieved when the opponent has not borne off a single stone.
  "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."
• (rare) Backgammon (the game itself).
  "We started about 7:00 drinking beers and playing gammon. Then after getting a little “loose” we went to a girls dorm."

noun

• (nautical) A rope fastening a bowsprit to the stem of a ship (usually called a gammoning).

noun

• (dated) Chatter, ridiculous nonsense.
  "Some people maintains^([sic]) that an Englishman's house is his castle. That's gammon."