Special attire making one irritable (6)
I believe the answer is:
livery
I believe this is a double definition.
'special attire' is the first definition.
(special or formal uniform)
'one irritable' is the second definition.
(livery can mean irritable due to a liver problem)
'making' is the link.
(Other definitions for livery that I've seen before include "Feeding and stabling of horses for money" , "outfit in uniform" , "Irritable" , "The stabling and care of horses" , "Fancy dress for footmen" .)