In short, a state of complete and utter trashedness!
(2) adj. an extreme state of intoxication by way of drugs or alcohol such that the subject's ability to perform basic tasks such as walking and talking are significantly impared.
In New Zealand and Australian slang, 1 is the more common sense, and in UK slang 2 is more common.
(2) I got so munted last night, I don't remember how I got home.