Go away and sing some jazz (4)
I believe the answer is:
scat
I believe this is a double definition.
'go away' is the first definition.
(informal term meaning to leave a place)
'sing some jazz' is the second definition.
(scatting is a style of singing in jazz)
'and' is the link.
(Other definitions for scat that I've seen before include "Animal droppings - small silvery fish" , "Get away with cats" , "One way of singing" , "way to sing > "Go away!"" , "unwelcome person may hear this" .)