One harasses guys in Twin Peaks (9)
I believe the answer is:
tormentor
'one harasses' is the definition.
(someone who harasses people)
'guys in twin peaks' is the wordplay.
'twin peaks' can mean two replacements for 'peak'.
'guys' becomes 'men' (guy can mean a man).
'in' indicates putting letters inside.
'peak' becomes 'tor' (a tor is a rocky peak).
'peak' becomes 'tor' (a tor is a rocky peak).
'tor'+'tor'='tortor'
'men' placed into 'tortor' is 'TORMENTOR'.
(Other definitions for tormentor that I've seen before include "Person causing" , "One giving great pain or annoyance" , "One harrying" , "One harassing" , "Inflictor of pain or anguish" .)