Leave, singing (4)
I believe the answer is:
scat
I believe this clue is a double definition.
'leave' is the first definition.
(I know this)
'singing' is the second definition.
(I know that scat is a type of singing)
(Other definitions for scat that I've seen before include "Jazz singing - animal droppings - silvery fish" , "Improvised jazz singing" , "Get away with cats" , "Jazz-singing" , "Wordless jazz singing" .)