That one monstrous and disgusting fart you've been holding since the beginning of the day and has built up the most horrid smells, only to be let out all at once once you open the front door of your house.
Dad: HEY guess who's back from work? Just so you all know, the whole house is about to stink from my foul den fart I just let out!
by Rich Gucci Flex July 14, 2018
A small room, commonly a closet, that has been dubiously filled with the ranky dank aromas of multiple individuals’ nasty diarrhea farts.
Mike: Dude, did you catch a whiff of that fart den at Michael’s?
James: Hell no, fart dens are gay as fuck.
Mike: Your loss, bro.
James: Hell no, fart dens are gay as fuck.
Mike: Your loss, bro.
by A Smelly Black Anus January 3, 2018