Plaintive poem or lament (5)
I believe the answer is:
elegy
I believe this clue is a double definition.
'plaintive poem' is the first definition.
(I've seen this before)
'lament' is the second definition.
(synonyms)
(Other definitions for elegy that I've seen before include "Poem penned beside church" , "Poetic lament for the dead" , "Sad work" , "Song of lament" , "Sad or reflective poem" .)