A hearing finishing early in chambers (5)
I believe the answer is:
atria
'chambers' is the definition.
(atrium is a kind of chamber)
'a hearing finishing early' is the wordplay.
'hearing' becomes 'trial' (I've seen this before).
'finishing early' means to remove the last letter.
'trial' with its last letter taken off is 'tria'.
'a'+'tria'='ATRIA'
'in' is the link.
(Other definitions for atria that I've seen before include "Central areas in buildings; open to the sky" , "Central courts, halls" , "Roofed central courts" , "Apartments" , "Open courts of Roman houses" .)