1: A general term used to describe "stuff"
2: A feeling of "bla"/ out of place/like shit/ect.
3: what one says when there is nothing of interest to say in hopes of starting a new, exciting conversation.
4: Nothing and everything
5: You may also sub this word in for a more clean and "kosher" sentence
1: Mom; what have you been doing on the computer all day?
Me; nothing important, just niss-niss
2: I've been feeling like niss-niss all day, today.
4: I've been doing niss-niss all day, yeah.
5: What the niss-niss are you guys doing up there?