To harrumph is to clear the throat noisily in disapproval. He harrumphed, a loud harrumph, harrumph at the suggestion.
It is a way of objecting without having to say anything you could be held to, which is why it belongs to committees and to elderly colonels in fiction. The word is imitative, made from the sound itself, and it works as a noun too.
1verbharrumphTo clear the throat noisily in disapproval.
“The old colonel harrumphed loudly when the young officer questioned his orders.”
harrumph is a sound of disapproval.
harumph imitative of the sound.
Etymology from Wiktionary, CC BY-SA
Practised in A Song of Ice and Fire