Aggressive action taken by those insulted (7)
I believe the answer is:
offence
'aggressive action' is the definition.
(I've seen this before)
'by those insulted' is the wordplay.
I cannot quite understand how this works, but
'by' could be 'of' and 'of' is present in the answer.
The remaining letters 'fence' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'taken' acts as a link.
Can you help me to learn more?
(Other definitions for offence that I've seen before include "The action of attacking an enemy" , "An illegal act, cause of annoyance" , "Misdemeanour" , "Discourtesy" , "taken by one insulted" .)