"Aquarius" musical (4)
I believe the answer is:
hair
'aquarius musical' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for hair that I've seen before include "Whiskers" , "Fur - mop" , "1960s' rock musical with nudity" , "Thread-like strands on the body" , "Musical - locks" .)