Mournful poem (5)
I believe the answer is:
elegy
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mournful poem</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for elegy that I've seen before include "Poem penned beside church" , "Sad or reflective poem" , "Poem for the departed" , "Poem as Gray's in churchyard" , "A sorrowful poem - Gray wrote a famous one" .)