Napping, shearing or sueding whatever you think of, they all are used to raise fibers from the fabric surface. These all are finishing types to improve the softness and comfort of the fabric.
Napping is done to get a deep hairy surface. This process involves passing the fabric over revolving cylinders covered with fine wires with small hooks on the ends. Flannelette, wool flannel, velours, fleeces etc are the example of napped sample.
Shearing is a process by which protrude fibers from the surface of a fabric, are cut the raised nap to a uniform height. The fun fact is the machine is operated like lawnmowers. There is a spiral cutter rotates against a stationary blade and cuts off any material protruding from the fabric surface. The main purpose of shearing is to smoothen the fabric surface by cutting raised fibers to a uniform height. And the napped fabrics are sheared to give an even pile height.
Sueding is done to cut surface fibers and produce a fuzz, a suede-like surface on the fabric. Sueding can be carried out in both the dry and wet state.