Loyalist leader of Protestants attending disturbance (7)
I believe the answer is:
patriot
'loyalist' is the definition.
(thesaurus)
'leader of protestants attending disturbance' is the wordplay.
'leader of' says to take the initial letters.
'attending' becomes 'at' (I've seen this in other clues).
'disturbance' becomes 'riot' (I've seen this before).
The initial letter of 'protestants' is 'p'.
'p'+'at'+'riot'='PATRIOT'
(Other definitions for patriot that I've seen before include "A trip to (anag.)" , "One loving their country" , "Defender of country" , "Loyal citizen" , "Flag waver" .)