Rogue artist's beginning to collude with gangster (6)
I believe the answer is:
rascal
'rogue' is the definition.
('rascal' can be a synonym of 'rogue')
'artist's beginning to collude with gangster' is the wordplay.
'artist's' becomes 'ras' (Royal Academician, member of Royal Academy of Arts).
'beginning to' indicates taking the first letters.
'with' is a charade indicator (letters next to each other).
'gangster' becomes 'al' (Al Capone).
The initial letter of 'collude' is 'c'.
'ras'+'c'+'al'='RASCAL'
(Other definitions for rascal that I've seen before include "Scoundrel or mischievous child" , "Cad" , "Lascar (anag.)" , "Mischievous or cheeky child" , "'Scoundrel, rogue (6)'" .)