A person place or thing so ugly that an additional u must be inserted into ugly to do the person place or thing justice
Marzipan is one Uugly cartoon character. She looks like a broom with a dress.
by SexBomb August 13, 2003
Uugly (pronounced-You-gly) means double ugly.
Man, that chick ain't just ugly, Shes Uugly.
by Vdubbs March 21, 2008
I think the extra U emphasizes the insertion of the word "You" as in You Ugly.
A perfect example can be found in Flick - Wild Cats.

"U-G-L-Y...you ain't got no alibi Uugly, Uugly...yo mama say Uugly"
by D. Ferrel September 24, 2003