Magical Theory by Adalbert Waffling
"Yes, there was a commotion outside the door and it flew open, and there was that rather uncouth barman standing with Snape, who was waffling about having come the wrong way up the stairs..."
- Professor Trelawney (HBP25)
Originally (when referring to a small dog) to yap or bark – the word “waff”‘s sound imitates a puppy’s bark (NSOED). When referring to the noises people make, the word has come to mean empty or aimless talk or writing, and can be used as a noun to describe the sense-free noises themselves or as a verb to mean the act of producing them.