Slow sentimental song (6)
I believe the answer is:
ballad
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">slow sentimental song</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 ballad that I've seen before include "Form of verse" , "Lay, narrative song" , "Simple song or poem" , "Narrative song with a recurrent refrain" , "delivered by singer" .)