An economic class made popular by Frank Reynolds in the TV show It's Always Sunny in Philadelphia. The "fringe class" refers to a set or group of individuals who have sufficient resources to lead a luxurious life; but instead chose to live a reckless, bohemian lifestyle with little to no regard for the quality of their life.
Tim is hanging out at the public pool even though he could get into the nicer private pool because he doesn't give a shit; he's fringe class.
by Slim_peter June 13, 2017