Play a mean sax (4)
I believe the answer is:
wail
'play a mean sax' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for wail that I've seen before include "blub" , "Lamentation" , "Long cry, sounds like cetacean" , "Utter a long sad cry" , "Lament audibly" .)