Graveyard shift in cop's role (10)
I believe the answer is:
necropolis
'graveyard' is the definition.
(synonyms)
'shift in cop's role' is the wordplay.
'shift' indicates anagramming the letters.
'in'+'cops'+'role'='incopsrole'
'incopsrole' with letters rearranged gives 'NECROPOLIS'.
(Other definitions for necropolis that I've seen before include "Large ancient cemetery" , "burial site" , "Ripon Close (anag) - cemetery" .)