xchat

Means "wrong chat". Typically used in MMORPG chat when you type in the wrong chat, such as Guild Chat instead of Party Chat. Can also be used when you send something to the wrong person in case of instant messaging.

Adrian: Hey John, when are you coming over today?
Mark: ????
Adrian: Oh, xchat. I thought you were John.

ketaka

Tunisian word for a person with big stomach. Someone who eats a lot.

Cookie: "I want more nuts!"
Cookie's Dad: "Don't be a ketaka!"