Subterranean cemetery (8)
I believe the answer is:
catacomb
'subterranean cemetery' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for catacomb that I've seen before include "underground vault" , "Underground Roman burial place" , "burial site" , "Place to bury" , "Burial chamber with vaulted tunnels" .)