A contemptible person on a hill who appeals to the mob? (8)
I believe the answer is:
agitator
'who appeals to the mob?' is the definition.
(someone agitating a mob of people)
'a contemptible person on a hill' is the wordplay.
'contemptible person' becomes 'git' (git can mean an annoying person).
'on' is a charade indicator (letters next to each other).
'hill' becomes 'tor' (tor is a kind of hill).
'a'+'git'+'a'+'tor'='AGITATOR'
(Other definitions for agitator that I've seen before include "Rabble-rouser - blender" , "One fomenting trouble" , "One stirring up (things)" , "Fomenter of unrest" , "Agent provocateur" .)