Does anyone know the meaning of Privy Counsel in the title of the Book "The Clouds of Unknowing"?

There is a book on christian mysticism by an unknown author for the 14th century. In the title we read: “The Could of Unknowing and The Book of Privy Counsel”. I could not find out the meaning of the latter. As far as I know Privy Council is rather a political-religious organization and it does not have anything to do with mysticism!
Thanks in advance