Stands for butt fucking ugly. When someone is hideous enough, that it takes words combined to describe.
person 1: woah look at that obese girl, with warts all over, bad breath, bad body odor, hairy armpits, yellow messed up teeth, boogers hanging out of her nose, tons of ear wax, and a man voice
Third degree ugly; a combination of the words "butt fucking ugly"; when an person or object is so horrible looking that the words ugly or fugly just don't cut it.