What do sweepers do?

Answer 1

A Sweeper is a soccer player who plays in the midfield and who's job it is to get the ball and play it up to players in attack positions ie they "clean up" the ball from defense and turn it into an attack

Answer 2

Sweepers are the last line of defense before the goalkeeper. The sweeper's job is to get the ball away from the defensive zone as quickly as possible. If they can get it to a teammate, great; but usually the ball is simply booted downfield or out of bounds. If you see a defensive player who seems to kick the ball out of bounds a lot more than others, that player is probably the sweeper.