It may be taken by the injured (7)
I believe the answer is:
offence
'it may be taken by the injured' is the definition.
The definition suggests a singular noun which matches the answer.
This is all the clue.
Can you help me to learn more?
(Other definitions for offence that I've seen before include "Aggressive action" , "Misdeed" , "An act punishable by law" , "Peccadillo" , "taken by one insulted" .)