Law-breaking implement (3)
I believe the answer is:
awl
'implement' is the definition.
(awl is a kind of implement)
'law-breaking' is the wordplay.
'breaking' indicates anagramming the letters.
'law' is an anagram of 'AWL'.
(Other definitions for awl that I've seen before include "has its use at last" , "Pointed hand tool" , "Law about a drilling tool" , "Hole-piercing tool" , "Tool for hole making" .)