A player who tries to play in a bigger stakes game than their bankroll allows them to.
SoundPoker Says: When playing poker a player should base the stakes they play for by the amount of money which they can afford to play with. If a player who normally brings a bankroll of $100 to play at a 2/4 limit game, takes that same bankroll to a 10/20 game, they would be considered a minnow.
