Nay is and old-fashioned or dialect for word 'no'. E.g. "You only can say yea or nay about this judgment" And it also uses for emphasize the point you are making, means 'indeed'. E.g. : "English is not easy, indeed, we have to practice a lot to learn it." For the same sentence we can say: "English is not easy, nay, we have to practice a lot to learn it."

ralph, thanks

Yes it means "No" It is old English but it is still used in some places. When votes take place in Parliament for example they say you can vote Nay or Yay. We also have a little word called "Nay-sayers" - this is the name we give to people who are always saying no, or not allowing things to happen.