Better lift current duke - he won't fight (8)
I believe the answer is:
pacifist
'he won't fight' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'better lift current duke' is the wordplay.
'better lift' becomes 'pac' (I can't explain this - if you can you should believe this answer much more).
'current' becomes 'I' (symbol for electric current).
'duke' becomes 'fist' (put up your dukes).
'pac'+'i'+'fist'='PACIFIST'
Can you help me to learn more?
(Other definitions for pacifist that I've seen before include "Anti-war person, believes in peaceful settlements" , "Person who believes in resolving quarrels by peaceful means" , "One is opposed to violence as a means of settling disputes" , "literary genre getting no opening in time gone by" , "Person who believes in peaceful means, anti-war" .)