Stir up (trouble) (6)
(Other definitions for incite that I've seen before include "Provoke, set off" , "Encourage, urge" , "Egg on" , "Stir up, rouse to action" , "Urge, instigate" .)
'stir up trouble' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for agitate that I've seen before include "Keep moving" , "'Stir, excite (7)'" , "Foment" , "Disturb, cause to worry" , "Stir; tie a tag (anag.)" .)