Urban dictionary is a dictionary that can be edited by anyone. Just a few days ago I continuously pressed the 'random word' button to see what it would come up with and found that almost every entry it gave was a joke entry. If you come across regional slang you've never seen before, Urban Dictionary can be helpful in finding out what the slang means, but I certainly wouldn't rely on it. Always use it with caution, and only when no definition in a 'proper' dictionary fits t. The first definition of 'rotten' that Urban Dictionary provides is the proper one: "A word which can be used to describe or define something which is disgusting, yucky, smelly, unsightly or dirty." It can also be used to describe a person with a bad personality. I've never heard the other definition of rotten before. If it's ever used like that, it's definitely non-standard and very likely regional.

Hola Carmen, la pagina Urban Dictionary no la deberías usar cuando quieres saber el significado verdadero de una palabra porque ahí solo escriben la definición en slang/jerga. Si quieres saber lo que se significa una palabra ve a dictionary.com. Your English is great, by the way.

No, the definitions in the urban dictionary are usually slang that may have a localized meaning. I would not use that word that way were I am from.