Abuse principally from louts at Kilburn (4)
I believe the answer is:
flak
'abuse' is the definition.
(flak can mean abuse or criticism)
'principally from louts at kilburn' is the wordplay.
'principally' says to take the initial letters.
The initial letters of 'from louts at kilburn' is 'FLAK'.
(Other definitions for flak that I've seen before include "Shooting" , "Ground-to-air attack: verbal abuse" , "Severe criticism" , "heated disagreement" , "Anti-aircraft shells or adverse criticism" .)