Disconcert, agitate (8)
I believe the answer is:
unsettle
I believe this clue is a double definition.
'disconcert' is the first definition.
(I know that unsettle is a more specific form of disconcert)
'agitate' is the second definition.
(I've seen this in another clue)
(Other definitions for unsettle that I've seen before include "'Disturb, make uneasy (8)'" , "Trouble" , "Discompose" , "disturb with lunettes" , "Make someone ill at ease" .)