The term "chaser" has several meanings depending on its context.
1) In a drinking or social setting, it refers to someone who consumes alcohol in order to catch up with another person who is already drunk. This person is often referred to as the 'chaser'.
2) In sports such as rugby and football, a chaser is a player whose primary role is to tackle opponents and win back possession of the ball for their team.
3) In photography or filmmaking, a chase scene refers to a sequence where one character pursues another in an attempt to catch them or prevent their escape.