They were mouthing soundlessly at Dumbledore, apparently too appalled to speak.
Harry, Ron, Seamus, Dean, and Neville changed into their dress robes up in their dormitory, all of them looking very self-conscious, but none as much as Ron, who surveyed himself in the long mirror in the corner with an appalled look on his face.
The face of Cornelius Fudge appeared upside down over Harry; it looked white, appalled.
She seemed too appalled to speak.
There are no more uses of "appalling" in the book.
Show samples from other sources
The live in appalling conditions.
She has scheduled a news conference to respond to the appalling accusations.