Fighters end up restraining one drunk (7)
I believe the answer is:
militia
'fighters end up restraining one drunk' is the definition.
I can't tell whether this defines the answer.
'end up restraining one drunk' is the wordplay.
I cannot really see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
'drunk' could be 'lit' (slang term) and 'lit' is found in the answer.
'end up' could be 'mia' (I've seen this in other clues) and 'mia' is present in the leftover letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for militia that I've seen before include "Army of non-professional soldiers" , "levy" , "Citizen army" , "Fighting force raised from the civil population" , "Citizens army" .)