底牌dǐpái 1.扑克牌游戏中最后亮出来的牌。{last card in one's hand in a card game} 2.〈比喻fig.〉内情{inside story}: 摸清对方～,再考虑如何行动。{Let's find out what the other side is up to before considering our action.} 3.〈比喻fig.〉留着最后动用的力量{sth. kept as the last resort}: 不到万不得已,别打这张～。{Don't play this card unless absolutely necessary.}