Bill — magistrate (4)
I believe the answer is:
beak
I believe this clue is a double definition.
'bill' is the first definition.
(I know that bill can be written as beak)
'magistrate' is the second definition.
(informal term)
(Other definitions for beak that I've seen before include "Nose (slang)" , "Mandible" , "Magistrate (informal)" , "Bird bill; magistrate" , "Magistrate -- schoolmaster (old slang)" .)