Annoy or irritate (3)
I believe the answer is:
irk
I believe this clue is a double definition.
'annoy' is the first definition.
(I've seen this before)
'irritate' is the second definition.
(to irk is to irritate)
(Other definitions for irk that I've seen before include "Severely annoy" , "Get at" , "English river" , "Irritate, vex" , "Irritate, annoy" .)