Irritating, tedious (8)
I believe the answer is:
tiresome
I believe this is a double definition.
'irritating' is the first definition.
(I've seen this before)
'tedious' is the second definition.
(I know that tedious can be written as tiresome)
(Other definitions for tiresome that I've seen before include "Boring, annoying" , "Fatiguing; boring" , "Aggravating" , "'Tedious, irksome (8)'" , "Annoying, makes you fed up" .)