Jazz subgenre (5)
I believe the answer is:
bebop
'jazz subgenre' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bebop that I've seen before include "Type of jazz" , "music played in jazz club" , "Jazz genre" , "1940s' form of modern jazz" , "1940s' jazz characterised by virtuosity" .)