1 N-COUNT 未知数;未知因素 If you refer to someone or something as a wild card in a particular situation, you mean that they cause uncertainty because you do not know how they will behave. 未知数;未知因素

2 N-COUNT （给予没有正常参赛资格的选手准其参加比赛的）“外卡”;“外卡”选手 If a sports player is given a wild card for a particular competition, they are allowed to play in it, although they have not qualified for it in the usual way. You can also use wild card to refer to a player who enters a competition in this way. （给予没有正常参赛资格的选手准其参加比赛的）“外卡”;“外卡”选手

3 N-COUNT (用于代替任何字符或字符串的)通配符 A wildcard is a symbol such as * or ? which is used in some computing commands or searches in order to represent any character or range of characters. (用于代替任何字符或字符串的)通配符 [computing]