Definition from Wiktionary, the free dictionary
See also wildcard
Alternative forms 
- In card games, a card that can be assigned any value or used to substitute for any needed card.
- (sports) A competitor or team that is allowed to compete in a tournament despite not reaching the normal standards to qualify for inclusion.
- Kye Sun-Hui won an Olympic gold medal in Judo, despite being a wild card.
- (computing) a character that substitutes for other characters in regular expressions and globbing
a substitute character