1. Negative, no, to convey disagreeance.
2. Gives the subject a bad characteristic, feeling or appearance.
"You're nup" - The person you are saying this to is in some way undesirable, or is saying/performing/has performed something undesirable.
"Nup. This is nup." - Use of both word types is achieved here. The first occurance (1) showing disagreeance to something, followed by (2) to show that "this" is "nup" or undesirable.
2)Expression of disbelief, usually over something too good to be true.
Can be described as another way of saying 'get out'.
Person2: Ok NUPPP
2) Person1: I drank 6 four lokos, 24 beers and was only buzzed last night.