Glossary: Chin

A fighter's ability to take a punch and not go down. Most high-level fighters have good chins (as fighters with weak chins tend to get run out at the amateur or early pro phases of their careers), so a fighter with a "strong chin" is a master of absorbing punishment that would drop most other fighters. Having a good chin doesn't necessarily imply that a fighter is unskilled in general, but may be an indictment of his defensive skills.

aka beard

If a fighter with a strong chin is good, they are usually just described as having a good chin. A fighter with a strong chin but isn't very good is generally described as having a lot of heart.