Playing clarinets topless shows guts (8)
I believe the answer is:
entrails
'guts' is the definition.
(I've seen this before)
'playing clarinets topless' is the wordplay.
'playing' is an anagram indicator.
'topless' means to remove the first letter.
'clarinets' with its first letter taken off is 'larinets'.
'larinets' with letters rearranged gives 'ENTRAILS'.
'shows' is the link.
(Other definitions for entrails that I've seen before include "Innards, viscera" , "Intestines, guts" , "Intestines of animals" , "Bowels or intestines" , "Intestines found in latrines" .)