In poker, the term may also refer to the action that a player who has not folded may take; he can have his hand "mucked" if another player attempts to discard but one or more cards end up in the live players hand.
The phrase "mucking" in poker describes a scenario where a player, having not yet folded, is able to take an action if another player tries to discard cards, but those discarded cards end up being part of the hand of the remaining players.