Chooker = Chat Hooker: A girl that chats to guys in a bar in return for drinks or some other form of consideration or payment. It could be a pro, e.g. the girl that walks around bars selling shots and who chats as though she likes you for as long as you keep buying those shots. Or the amature that is simply on the look out for a cheap night and is willing to pretend to like you whilst you ply her with drinks.
My mate blew $300 on a chooker and the only thing he got up that night was the toilet lid and his guts!