Trim spliff in dodgy nightclub (4,5)
I believe the answer is:
clip joint
'dodgy nightclub' is the definition.
'trim spliff' is the wordplay.
'trim' becomes 'clip' ('clip' can be a synonym of 'trim').
'spliff' becomes 'joint'.
'clip'+'joint'='CLIP-JOINT'
'in' acts as a link.
(Other definitions for clip joint that I've seen before include "High-charging nightclub" , "Expensive nightclub" , "Club routinely defrauding patrons" , "Bar charging extortionate rate" , "Overpriced nightclub" .)