(in some card games) a card that belongs to the suit (= one of the four sets in a pack of cards) that has been chosen for a particular game to have a higher value than the other three suits（某些纸牌游戏的一张）王牌，主牌，将牌
something that gives you an advantage over other people, especially when they do not know what it is and you are able to use it to surprise them王牌；绝招；杀手锏
He was able to get what he wanted without having to play his trump card.他无需打出王牌就能得到自己想要的东西。
Many private schools use small classes as their trump card in marketing campaigns.许多私立学校在营销活动中都采用小班制作为王牌。