Insult lawyers and bishop (4)
I believe the answer is:
barb
'insult' is the definition.
(thesaurus)
'lawyers and bishop' is the wordplay.
'lawyers' becomes 'bar' (I've seen this before).
'and' is a charade indicator (letters next to each other).
'bishop' becomes 'b' (abbreviation used in chess).
'bar'+'b'='BARB'
(Other definitions for barb that I've seen before include "Backward-facing part of hook" , "A thorn or a gibe" , "Point of fish-hook - gibe" , "Slight" , "Sharp point; wounding comment" .)