A sports entertainer is usually an athlete that instead of participating in win/lose athletic events either singly or as a team, provides entertainment based on what looks like a sport or athletic event. The term "sports entertainer" or "sports entertainment" is predominantly used by World Wrestling Entertainment to describe what they do. Most of the audience knows that the wrestling matches are staged and fixed from the beginning, so the term "entertainment" is a more correct term to use instead of billing a show as an actual fight. It is also more appropriate since they have story arcs in between matches and some that stem from or lead to matches.
Another form of this is the roller derby.