I’d upset agents during month regarding the law (8)
I believe the answer is:
judicial
'regarding the law' is the definition.
'i'd upset agents during month' is the wordplay.
'upset' indicates an anagram.
'agents' becomes 'cia'.
'during' is an insertion indicator.
'month' becomes 'jul' (**).
'id' anagrammed gives 'di'.
'di'+'cia'='dicia'
'dicia' going into 'jul' is 'JUDICIAL'.
(Other definitions for judicial that I've seen before include "Relating to judges" , "Of lawcourts or the administration of justice" , "Relating to law courts" , "Relating to the administration of justice" , "Of a judge" .)