Describes, literally, any person or animal that can ambulate using legs or related appendages. Generally though it is used as the epitome of low standards in the selection of a mate of the opposite sex.
We all knew Ray would fuck anything that walks and swore by the saying pussy ain't got no face. But he outdid even himself when he was arrested for sneaking into Sea World with intent to engage in intercourse with the female dolphins.
Urbandictionary told you to look this up. So now you have. Why? You're a smartass. Or a blond/blonde. Either way, this is a total waste of your time and you've just lost about 4 minutes of your life from this useless piece of crap.
Congratulations.