Final answer:
In the Arthurian tale of Sir Gawain and the Green Knight, Sir Gawain gives the host of the castle a kiss after the host returns from hunting, following an agreement they made to exchange their respective winnings.
Step-by-step explanation:
The question relates to the exchange of winnings in Sir Gawain and the Green Knight, a chivalric romance that is a part of Arthurian legends.
After the host of the castle, who is actually Lord Bertilak, returns from hunting, Sir Gawain gives him a kiss. This is because Sir Gawain has entered into an agreement with the lord where he must give whatever he gains during the day in exchange for whatever the lord has hunted.
The kiss represents what Sir Gawain has received that day, which conforms to the rules of the game they are playing. This exchange is a significant part of the poem's plot, highlighting the themes of chivalry, honesty, and the tests of character.