Exasperates (5)
(Other definitions for riles that I've seen before include "Irritates, nettles" , "Annoys in American way" .)
(Another definition for vexes that I've seen is " Annoys".)
'exasperates' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for irks that I've seen before include "Annoys, vexes" , "'Irritate, annoy (4)'" , "Galls" , "Annoys, irritates" .)
(Other definitions for angers that I've seen before include "annoys" , "Winds up" , "Irritates" , "Outrages" , "Maddens" .)