The primary function of a goalie in sports, particularly in games like hockey and soccer, is to prevent the opposing team from scoring by guarding the goal. Goalkeepers are responsible for stopping shots on goal, which requires quick reflexes, strong positioning, and excellent hand-eye coordination. They often direct defensive plays and communicate with teammates to maintain a cohesive strategy. Additionally, goalies must anticipate the opposing team's moves and react swiftly, making their role crucial to a team's overall success and defensive stability.