Film depicting attorney lacking weight (5)
I believe the answer is:
layer
'film' is the definition.
(film can mean a thin layer of something)
'attorney lacking weight' is the wordplay.
'attorney' becomes 'lawyer' (synonyms).
'lacking' indicates named letters should be taken away.
'weight' becomes 'w' (short for weight).
'lawyer' with 'w' taken away is 'LAYER'.
'depicting' is the link.
(Other definitions for layer that I've seen before include "One of several thicknesses" , "Thickness of material or earth - relay it" , "Single thickness and hen" , "Stratum, tier" , "Single thickness, tier" .)