Song of mourning (5)
I believe the answer is:
elegy
'song of mourning' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for elegy that I've seen before include "Poem as Gray's in churchyard" , "Plaintive poem" , "Dirge" , "Poem for the departed" , "Poem lamenting the dead" .)