Rabble-rouser detailed musical direction (7)
I believe the answer is:
agitato
'musical direction' is the definition.
(I've seen this in another clue)
'rabble-rouser detailed' is the wordplay.
'rabble-rouser' becomes 'agitator' (I've seen this before).
'detailed' means to remove the last letter (the word must be end-less or 'de-tailed').
'agitator' with its final letter taken off is 'AGITATO'.
(Other definitions for agitato that I've seen before include "Musically, to be performed vigorously" , "scored frenziedly" , "in frenzied manner" , "stirring music" , "Restlessly (music)" .)