red card

Short definition from Wiktionary

Noun

1. 1
   A card displayed by the referee when a player is sent off for a serious infringement of the rules.
2. 2
   Any official instructions to vacate an area.
3. 3
   A card indicating a firefighter's qualifications and specialties.

Verb

1. 1
   To show (a player) a red card, and dismiss them from the playing area; to send off.