"Harrumph!," to Scrooge (3)
I believe the answer is:
bah
(Other definitions for bah that I've seen before include "Exclamation of disgust or annoyance" , "Disbelieving expression" , "''... Humbug'' Scrooge's cry" , "Exclamation of contempt or disgust - Scrooge used to say it" , "Comic expression of contempt" .)