Tool for the lawyer in a fight (7)
I believe the answer is:
bradawl
'tool' is the definition.
(bradawl is a kind of tool)
'lawyer in a fight' is the wordplay.
'lawyer' becomes 'da' (abbreviation for District Attorney).
'in' is an insertion indicator.
'a fight' becomes 'brawl' (brawl is a kind of fight).
'da' put within 'brawl' is 'BRADAWL'.
'for the' is the link.
(Other definitions for bradawl that I've seen before include "Boring article" , "Piercing tool" , "sharp-pointed object" , "Hole-making tool" , "one that bores" .)