Angers (5)
'angers' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for riles that I've seen before include "Irritates, nettles" , "Annoys in American way" .)
'angers' is the definition.
(irking is a kind of angering)
This is the entire clue.
(Other definitions for irks that I've seen before include "Annoys, irritates" , "'Irritate, annoy (4)'" , "Galls" , "Annoys, vexes" .)