Definition: If a poker player is called a 'donkey,' he's a bad player who makes blatantly bad poker plays. A weak player.
Donkey is also shortened to "donk" by many players to announce that they're playing badly or planning to, as in "I'm going to donk it up tonight."
Also Known As: fish
Last time I was at the card room, I got a table full of donkeys -- no one knew how to play at all.