Loyalist quietly attending disturbance (7)
I believe the answer is:
patriot
'loyalist' is the definition.
(I've seen this before)
'quietly attending disturbance' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'attending' becomes 'at' (I've seen this in other clues).
'disturbance' becomes 'riot' (I've seen this before).
'p'+'at'+'riot'='PATRIOT'
(Other definitions for patriot that I've seen before include "Tell perhaps" , "A trip to (anag.)" , "Country supporter" , "One with a strong love of country" , "One loving their country" .)