Ignoring It, it's the best horror film (6)
I believe the answer is:
scream
'horror film' is the definition.
(1996 horror film)
I don't understand how the remainder of the clue works.
(Other definitions for scream that I've seen before include "card" , "Utter a sudden loud cry" , "Make high shrill sound as from fear" , "Loud shrill cry" , "Piercing yell" .)