Backspin

Also known as Underspin.

A reverse spin that is applied by drawing the face of the racket down across the ball at impact, resulting in the top of the ball turning in the opposite direction to its forward movement (i.e. the top will turn towards the player who hit the ball).

Backspin is used by defensive players to return an opponent's topspin strokes from a distance. It imparts a lifting force on the ball, causing it to drop slower than by gravity alone.