Hitchcock classic (6)
I believe the answer is:
psycho
'hitchcock classic' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for psycho that I've seen before include "nuts" , "Well-known Hitchcock film" , "Method of treatment pioneered by Freud" , "Chopsy (anag.)" , "Bates Motel horror film" .)