Used by rabble-rouser, van terrorised man (7)
I believe the answer is:
servant
'man' is the definition.
(man can mean someone's personal servant)
'used by rabble-rouser van terrorised' is the wordplay.
'used by' indicates the answer is hidden within the clue.
'SERVANT' is hidden within 'rabble rouser van terrorised'.
(Other definitions for servant that I've seen before include "barmaid, for instance" , "'Flunky, lackey (7)'" , "Taverns (anag) -- retainer" , "Domestic attendant" , "One in domestic service" .)