Violent attacker is rolling, eg canned by lager? (8)
I believe the answer is:
besieger
'violent attacker' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for besieger that I've seen before include "Attacker attempting to capture" , "Invader" .)