Excite or trouble (7)
I believe the answer is:
agitate
I believe this clue is a double definition.
'excite' is the first definition.
(I know that excite can be written as agitate)
'trouble' is the second definition.
(I know that agitate is a more specific form of the action the trouble)
(Other definitions for agitate that I've seen before include "Unsettle" , "Incite" , "'Stir, excite (7)'" , "Disturb or shake" , "Trouble, make nervous" .)