Make uneasy or cause to be worried (7)
I believe the answer is:
perturb
'make uneasy or cause to be worried' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for perturb that I've seen before include "Bother" , "Make uneasy or cause to be worried" , "upset" , "Disturb - trouble" , "Disquiet, disturb" .)