(noun): A somewhat unwelcome female just who frequents bars of sick repute. Produced from the definition of for stale beer left in a single day in a bar's keg outlines; e.g. slag.The "slag" is dangerous, because she usually uses this lady natural habitat, the club, as a staging floor for her assault on unwitting intoxicated males. By surrounding by herself by alcohol, she guarantees that alcoholic beverages caused "beer goggles" will make up for her lack of aesthetic charm, and promiscuous reputation. After six beverages, a slag appears somewhat less haggard, along with her indiscretion will seem like a very important thing.History: Pioneered by UConn Alum checking out Narraganset RI. Barslag is just one more term of endearment for a club whore.