Group of solicitors walloped over regulations (4)
I believe the answer is:
laws
'regulations' is the definition.
(I've seen this in another clue)
'group of solicitors walloped over' is the wordplay.
'group of' indicates the answer is hidden within the clue (group of letters from the clue).
'over' shows that the letters should be reversed in order.
'swal' is hidden within 'solicitors walloped'.
'swal' back-to-front is 'LAWS'.
(Other definitions for laws that I've seen before include "code" , "Codes of action" , "Regulations" , "Rules, statutes" , "Rules imposed by authority" .)