Pronunciation: (sel'out"),[key] —n. 1. an act or instance of selling out.
2. an entertainment, as a show or athletic event, for which all the seats are sold.
3. Informal.a person who betrays a cause, organization, or the like; traitor.
4. Informal.a person who compromises his or her personal values, integrity, talent, or the like, for money or personal advancement.