A short sound created with the vibration of the lips; used for expressing disgust, sarcasm, attitude, or to just sound like a horse and annoy the hell out of people.
Person #1: "So, are you going to give me that money that you owe me?"
in which the h-sound is produced in the back of the throat and the 'a' is silent, is the sound one makes to emphasize how empty an action, reaction or situation is.