Strong law is broken in the beginning (8)
I believe the answer is:
stalwart
'strong' is the definition.
(thesaurus)
'law is broken in the beginning' is the wordplay.
'is broken' indicates anagramming the letters.
'in' means one lot of letters goes inside another.
'the beginning' becomes 'start' (start is a kind of beginning).
'law' is an anagram of 'alw'.
'alw' inserted within 'start' is 'STALWART'.
(Other definitions for stalwart that I've seen before include "Indomitable" , "Walt's rat is strong and brave" , "Staunchly faithful" , "Determined" , "husky" .)