Man with bow could be cheating (2,3,6)
I believe the answer is:
on the fiddle
'be cheating' is the definition.
(I've seen this before)
'man with bow' is the wordplay.
I cannot quite see how this works, but
'man' could be 'he' and 'he' is located in the answer.
This explanation may well be incorrect...
'could' acts as a link.
(Other definitions for on the fiddle that I've seen before include "Involved in swindling" , "leader of the orchestra?" , "Running a racket" , "Engaged in cheating" , "Cheating (colloq.)" .)