H'mm. For some reason, "jolie laid" is the first response that comes to mind; a woman so "ugly" that she is beautiful.
When I use the word "ugly" myself it does tend to the bad. I find it springs to mind when someone is being particularly nasty, unkind, selfish, or mean.
Just now I took down my copy of the Pocket Oxford Dictionary to find this:
ugly (adj.) Unpleasing or repulsive to sight; morally repulsive, vile, unpleasantly suggestive, threatening; formidable antagonist; ugly duckling person who turns out the genius of the family after being thought the dullard
Yes, that'll do for definition(s).