The Inner Eye,’ said Professor Trelawney with dignity, straightening her shawls and many strands of glittering beads, ’was fixed upon matters well outside the mundane realms of whooping voices.’
Then Cadwallader scored again, making things level, but Luna did not seem to have noticed; she appeared singularly uninterested in such mundane things as the score, and kept attempting to draw the crowd’s attention to such things as interestingly shaped clouds and the possibility that Zacharias Smith, who had so far failed to maintain possession of the Quaffle for longer than a minute, was suffering from something called "Loser’s Lurgy."
Concentrating with all his might he thought, "I need to see what Malfoy’s doing in here… I need to see what Malfoy’s doing in here… I need to see what Malfoy’s doing in here…" Three times he walked past the door; then, his heart pounding with excitement, he opened his eyes and faced it — but he was still looking at a stretch of mundanely blank wall.
There are no more uses of "mundane" in the book.
Show samples from other sources
I’m going to have to spend all of Saturday running errands and doing mundane chores.
Her art mesmerizes us with mundane objects by blowing them out of proportion.