a yellow-coloured card, shown to a player, (especially in Association Football), as a caution that he has committed a flagrant foul; a further such foul would result in a red card
In football or rugby, if a player is shown the yellow card, the referee holds up a yellow card to indicate that the player has broken the rules, and that if they do so again, they will be ordered to leave the pitch. a yellow card held up by a football referee to show that a player has done something wrong red card