best card

Meaning

1. sb's best / strongest / winning card

   something that gives sb an advantage over other people in a particular situation

From the same entry

• get your cards
• give their cards
• have a card up your sleeve
• hold all the cards
• hold your cards close to your chest
• lay your cards on the table
• on the cards
• play the… card
• play your cards right
• tip your hand
• the cards are stacked against you
• the cards are stacked in your favour