Undertaker's vehicle (6)
I believe the answer is:
hearse
'undertaker's vehicle' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for hearse that I've seen before include "Funeral car" , "Carriage for a corpse" , "Vehicle for carrying the dead" , "Vehicle for conveying a coffin" , "Undertaker's car" .)