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2.
Nyay: An exclimation of great joy. Usually in a situation that was originally bleak and most often followed by a feeling of extreme crunktitiude.
Andy: Ian, it turns out the shop burned down and we don't have to go to work!

Ian: NYAY!
by Andy & Ian October 25, 2004
 
1.
A replacement for the word yay, most oftenly placed at the end of the phrase. usually said in a cutsie-poo voice.
Tonight is going to be so much fun, Nyay!
by Tateamus James March 23, 2009