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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.
by nguyeny-pants January 27, 2014
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