Disturb, unnerve (7)
I believe the answer is:
agitate
I believe this clue is a double definition.
'disturb' is the first definition.
(I know that agitate is a more specific form of disturb)
'unnerve' is the second definition.
(thesaurus)
(Other definitions for agitate that I've seen before include "Stir; worry" , "Stir violently" , "Make troubled or nervous" , "Stir; arouse" , "cause trouble" .)