Peripheral characters killed in outstanding film (5)
I believe the answer is:
alien
'film' is the definition.
(1979 film)
'peripheral characters killed in outstanding' is the wordplay.
'peripheral characters killed in' means to look at the middle letters (letters at the periphery are removed).
'outstanding' becomes 'salient' (synonyms).
The middle letters of 'salient' are 'ALIEN'.
(Other definitions for alien that I've seen before include "ET" , "Foreign; extraterrestrial" , "coming from overseas" , "Offensive" , "of foreigners" .)