Hearing that is very irritating (6)
I believe the answer is:
trying
This clue could be a double definition.
'hearing' is the first definition.
('try' can be a synonym of 'hear')
'very irritating' is the second definition.
'trying' can be an answer for 'irritating' (thesaurus). I am unsure of the 'very' bit.
'that is' is the link.
Can you help me to learn more?
(Other definitions for trying that I've seen before include "irksome" , "Doing one's best - annoying!" , "Essaying" , "Putting into dock" , "Attempting; difficult" .)