A fork of Rural Dictionary
A rather large woman who is not a BBW, but rather a BFN. Her lady lumps do not inspire any recollection of beautiful things like some chunky women might offer, but rather leave a sour taste in your mouth after you throw up a little. BFN typically Photoshop their selfies in an attempt to justify their ugly lifestyle choices.
Dude 1: Hey man, did you just see that Big Fat Nasty? Dude 2: What is that, a cheeseburger? Dude 1: No man, it's thunder-thighs and butt cheese! Dude 2: Gross.