The word hock has several meanings:

1. To pawn something, meaning to leave a valuable item at a special shop called a pawnshop in exchange for quick cash, with the promise to buy it back later. When someone is desperate for money, they might hock their guitar or jewelry. If they can't pay the money back with interest, the pawnshop keeps the item and sells it. People sometimes say they're “in hock” when they owe money they're struggling to repay.
2. The joint in the middle of an animal's back leg, like the ankle on a horse or dog. If you watch a horse trot, you can see its hocks bend and flex with each step. Veterinarians pay close attention to hocks because problems there can make it hard for animals to walk or run properly.
3. To sell or peddle something aggressively, often something of questionable quality. A street vendor might hock cheap sunglasses, while a loud salesperson might hock miracle cleaning products on TV. This usage suggests pushiness: the seller is working hard to unload their goods, whether you want them or not.