A nickname of the township outside of Philadelphia called Upper Darby. It is called this because its full of scum, and roughly 2 of 3 girls are pregnant. Only about 5% of the Upper Dirty population take showers on a regular basis, and all these facts lead to the nickname.
No wonder those kids are such scumbags; They're from Upper Dirty.
po J. Wolff Мај 15, 2006