Neither yes, neither no, in fact both yes and no (and possible a recursive nyez, sometimes).
The word is strongly related to the principles of Quantum Mechanics - it's all about probabilities.
Like a quantum state, the word is yes and no (and a lot more) at the same time.
This is the word that could be used as an answer to any question.
Q: Are you single or not ?
A: Nyez !
Q: What did Adriana and A-P. Stegelius do with their car?
A: Nyez !?