Urban Trash

Like White Trashonly that person(s) live in an urban area while maintaning their white trash ways.

all of the stupid definitions you have to weed through on Urban Dictionary, always consist of some guy writing about a girl he'll never fuck.

The phenomena on Urban Dictionary of submitting a name, then writing a definition for a singular person painting them in a negative light.
If male, the definition will either claim the subject is homosexual, possesses a small penis, or is a "douchebag." If female, the definition will describe her as a "slut," a "bitch," or "fat."
A slightly intelligent Trash-Talker will try to disguise their entry with things like "he/she," or using the name in question as a title. This will (sadly) fool some editors.
Urban Dictionary Trash-Talking is widespread, with about 40% of entries reviewed being UDTT or UDA.
The converse is Urban Dictionary Arrogance.