nup - (1) interjection (2)adjective:
1. Negative, no, to convey disagreeance.
2. Gives the subject a bad characteristic, feeling or appearance.
In the case of (2) this is a contextual word, ie: the use of the words around it define the exact meaning of nup.
"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.