A bertlow is anyone who lives in the bad part of town, has had 50 different jobs in 3 months, etc. Also known as a loser, scrub, etc. Comes from Wickenburg, AZ, where a man named "Bertlow" was such a loser that the town's youth started calling all losers "bertlow".
"Jon is such a bertlow"
"All the bertlows live out at Whispering Ranch."