barbarian, n.: 1. in general usage, a member of a culture considered to be inferior by the speaker, or lacking advanced material culture (literature, written law, architecture, etc.). 2. in gamerese, a warrior of a culture more primitive than average for the milieu, usu. inspired by the historical vikings or by the Conan novels of Robert E. Howard. 3. in D&D, a fighter class prone to frenzy and hatred of magic. [GJ1]
Addendum: Newbies love to play barbarians because the concept gives them free license to smash everything in sight and harass spellcasters. Barbarians usually run around without a shirt on and without armor, although I have no recollection of any viking, or Conan, ever being so stupid. [GJ1]