Crook soundly attacked... (5)
I believe the answer is:
felon
'crook' is the definition.
(I know that crook can be written as felon)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for felon that I've seen before include "Law-breaker" , "Malefactor" , "A dealer in textile" , "sore" , "Serious criminal" .)