Uglayass is A word that doesn't even mean someone can be ugly. Someone would use this term when they are mad or they just simply don't like a person they call them this. You have to say it with an accient . You have to exaggerate they "A" in uglAAAAyass. First you say ug then laaaaaaay then ass but don't really say the "ss". Anyone can use this word.
You could be the prettiest person on earth, but if I don't like you, you better believe I'm calling you an uglayahh.

to tell someone to calm down and relax.