The plural form of nay is nays.

How do you properly use nay?

You use nay in front of a stronger word or phrase which you feel is more correct than the one you have just used and helps to emphasize the point you are making. Long essays, nay, whole books have been written on this.

Is it yea or nay yay or nay?

Writing 'yay or nay' instead of 'yea or nay' is one of the most common misspellings in the English language. The correct way to use the idiom is 'yea or nay' or 'aye or no. ' By itself, we only use the word yay as an exclamatory or for verbal depictions of measurement.