Scoff - to eat hurriedly/quickly o without manners and politeness. To eat and not share etc
Scoff - to be up-aty and pompous at (but not including) others views/opinions/matters of state/fashion/choice. To 'be above others'. To disbelieve certain things ie. 'I can't believe that!' he scoffed.
I'm not sure about this but it could also mean - to make uncertain noises of the throat and mouth insinuating disbelief o to find something disgusting