Mess around with violin (6)
I believe the answer is:
fiddle
I believe this is a double definition.
'mess around' is the first definition.
(thesaurus)
'violin' is the second definition.
(I know that violin can be written as fiddle)
'with' is the link.
(Other definitions for fiddle that I've seen before include "Deception" , "Violin - racket" , "Scam - musical instrument" , "tinker" , "Cook" .)