Silent animated Disney film, unfinished (4)
I believe the answer is:
dumb
'silent' is the definition.
(I know that silent can be written as dumb)
'animated disney film unfinished' is the wordplay.
'animated disney film' becomes 'dumbo'.
'unfinished' means to remove the last letter.
'dumbo' with its last letter taken off is 'DUMB'.
(Other definitions for dumb that I've seen before include "Silent" , "Lacking intellectual acuity" , "Stupid; unable to speak" , "Incapable of speech" , "Stupid (sl.)" .)