A drop shot is a shot in some racquet sports in which the ball (or birdie) is hit relatively softly, and lands just over and close to the net.
A good drop shot requires great touch. The ball should bounce low and near the net, sometimes with underspin (or backspin). Backspin slows the ball and decreases the height of its bounce. In some extreme cases, the ball will bounce back towards the net. Sidespin may also be put on the ball so it kicks sideways when it bounces. A bad drop shot is one that travels too deep into the court, or bounces too high. When this happens, the opponent can get to the ball, and make an easy play.
A drop volley is simply a drop shot used as a volley. The secret to making a good drop volley is having "soft hands." To achieve this, a player slightly loosens his or her grip on the raquet at the moment of impact with the ball. This allows the racquet to absorb more force and reduces the ball's rebound.