enforcer
1. Someone who serves as a protector and/or keeps others from acting in an unwelcome manner, as through the use of physical strength or intimidation. I always keep a few enforcers around me for protection. We need an enforcer out here to make sure people don't push their way into the store when it opens.
2. In sports, especially ice hockey, a player who uses their physical strength to intimidate opponents and protect teammates. Their enforcer is out with an injury, so we should be able to push their smaller players around tonight.