Body snatching is the act of removing a corpse from its gravesite, and then stealing it. There are many reasons as to why a person would be willing enough to break the law and steal a body. One reason is that they could sell the bodies to medical or anatomical schools, and get a good sum of money from them. For example, many of the earlier models of the human skeleton were in fact the remains of a real person, and not artificial. This practice was normally done in India, and laws were established as an attempt to stop those crimes.
As you can guess, many people look down upon those who steal corpses from their respective gravesites and cemetaries.