Mournful bell toll (5)
I believe the answer is:
knell
'mournful bell toll' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for knell that I've seen before include "Sound of tolling bell" , "Toll (bell)" , "''The curfew tolls the ... of parting day'' (Thomas Gray)" , "Solemnly proclaim death" , "Funereal bell sound" .)