A duster is somebody who is worthless; a loser. Somebody who isn't good at anything.
Usually used by athletes to describe someone who is horrible or worthless at
a sport. Usually the worst player on their team, and as a result all they do is sit around and
collect dust, hence the term "duster".
Jake is such a duster. In
gym class all he does is
stand in the corner while we play
dodge ball.