'Ugly' means unpleasant, repulsive or less than acceptable, according to normal standards. It also means disagreeable or objectionable, hence it has connotations of 'unexpected' or 'unconventional'. Though traditionally a pejorative term, where 'ugly' is worn with pride, it can serve as a powerful denonym that positions its subject as an underdog, ie. 'ugly duckling'.
A good example of this is the blatant use of 'ugly' as a label in online dating. This web site is under construction, but if you are looking for ugly people to date, try one or both of the sites below.
Ugly Schmucks | Date Ugly People