Film showing right slippery customer? (4)
I believe the answer is:
reel
'film' is the definition.
(I know that reel is a type of film)
'right slippery customer?' is the wordplay.
'right' becomes 'r' (common abbreviation).
'slippery customer?' becomes 'eel' (I've seen this in another clue).
'r'+'eel'='REEL'
'showing' acts as a link.
(Other definitions for reel that I've seen before include "Move unsteadily (like a Scottish dancer?)" , "Show astonishment" , "Scottish/Irish dance" , "Cylinder on which something is wound" , "Fishing rod attachment" .)