A style of daytime dress popular at many US universities where members of fraternities go to great pains to appear to be homeless.
Typical attire includes boat shoes or Wallabies missing the laces, gym shorts, and a hideously stained, presumably once white t-shirt. Hair should be disheveled at best.
To dress up as Carl for halloween, his fraternity brother donned a fratty vagrant style, wearing gym shorts, an undershirt, boat shoes, and smeared Crisco in his hair. Even his girlfriend couldn't tell the difference.