In season 4 episode 6, Oberyn addresses Varys as "Lord Varys." Varys notes that no one is under any obligation to call him "lord," but Oberyn shrewdly notes that everyone calls him that anyway. Does Tywin Lannister ever address Varys as such, on the show or in the books?
Does Tywin Lannister ever address Varys as such, on the show or in the books?
Lord Tywin references him as such in A Storm of Swords, Chapter 72, but as Varys is not in the room at the time that may not meet your definition of addressing him.
"Heal him," Lord Tywin said again, vexed. "You are aware that Lord Varys has sent fishermen into the waters around Dragonstone. They report that..."
As Lord Tywin
soon thereafter, we may never know if he addressed Varys by that title to his face.