black·jack 
(blăkjăk′)
(blăkjăk′)n.
1. A leather-covered bludgeon with a short, flexible shaft or strap, used as a hand weapon.
2. Games A card game in which the object is to accumulate cards with a higher count than that of the dealer but not exceeding 21. Also called twenty-one, vingt-et-un.
3. Sphalerite.
tr.v. black·jacked, black·jack·ing, black·jacks
1. To hit or beat with a blackjack.
2. To coerce by threats.