Prisoner released by nobleman not a violent drunk? (5,4)
I believe the answer is:
lager lout
'a violent drunk?' is the definition.
(a lager lout is an aggressive drunken person)
'prisoner released by nobleman not' is the wordplay.
'prisoner' becomes 'lag' (slang term).
'released' becomes 'out' (eg out of prison).
'by' means one lot of letters go next to another.
'nobleman not' becomes 'erl' (I can't justify this - if you can you should give a lot more credence to this answer).
'out' after 'erl' is 'erlout'.
'lag'+'erlout'='LAGER LOUT'
Can you help me to learn more?
(Other definitions for lager lout that I've seen before include "Aggressive young drunk" , "Drinker behaving antisocially" , "Troublesome drunk" , "menace" , "Alcohol-fuelled youth" .)