1 [plural] also trump American EnglishDGC
the suit (=one of the four types of cards in a set) chosen to have a higher value than the other suits in a particular card game:
Hearts are trumps.
2 also trump cardDGC
a card from the suit that has been chosen to have a higher value than the other suits in a particular game
something that you can do or use in a situation, which gives you an advantage:
But then he decided to play his trump card (=use his advantage).
They hold all the trump cards (=have things which could give them an advantage).
to provide what is needed, especially unexpectedly and at the last moment:
Paul came up trumps and managed to borrow a car for us.