Spooks (6)
(Other definitions for agents that I've seen before include "Instruments" , "travelling salesmen" , "Representatives" , "Spies" , "Factors" .)
'spooks' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for scares that I've seen before include "Frightens or intimidates" , "Causes fear" , "Terrifies" , "Affrights" , "Alarms" .)