Composer disturbed brutes outside church (8)
I believe the answer is:
schubert
'composer' is the definition.
(Franz Schubert, 1797-1828)
'disturbed brutes outside church' is the wordplay.
'disturbed' is an anagram indicator (the order of letters is disturbed).
'outside' is an insertion indicator.
'church' becomes 'ch' (common abbreviation).
'brutes' anagrammed gives 'subert'.
'subert' going around 'ch' is 'SCHUBERT'.
(Other definitions for schubert that I've seen before include "Butchers (anag) - composer, d. 1828" , "Lieder composer" , "barman" , "Austrian composer and prolific songwriter" , "Butchers embrace great German composer" .)