Vocalise musically (4)
I believe the answer is:
sing
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">vocalise musically</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sing that I've seen before include "Chant" , "serenade" , "Celebrate" , "Turn informer" , "Make melodious sounds with voice" .)