Idiom Magic : 不可捉摸的人; 難以預測的事物 A/THE WILD CARD

【明報專訊】In card games a wild card is a card that has been assigned (被分 派) a special value or number. Idiomatically, it is something or someone whose qualities are unknown (未知的). "We should do well in the swimming event, but there's a wild card from Singapore on our opponent's team who is said to be awfully good. We'll have to keep an eye on her." "The election result (選舉結果) was a complete surprise, and the wild card candidate Dion Leung has become our class president!"