According to the search results from Urban Dictionary, a "booster" is a person who steals items from retail stores and resells them on the black market. Boosters usually steal cars, clothing, jewelry, and other retail items. They sell these items on the streets, usually for a discounted price. The term "boosting" is used to describe the act of stealing retail items and reselling them on the black market. It is important to note that the term "booster" has other meanings in Urban Dictionary, such as "boost" meaning something that is untrue, or "booster shot" meaning to be victimized in the degrading act of forced anal sex while detained or incarcerated.