Hard — of hearing? (6)
I believe this clue is a double definition.
'hard' is the first definition.
(similar in meaning)
'hearing?' is the second definition.
('try' can be a synonym of 'hear')
'of' acts as a link.
(Other definitions for trying that I've seen before include "Taxing" , "Annoying; sampling" , "Vexatious - having a go" , "Hearing (a case)" , "occupation of Oliver Wendell Holmes Jnr" .)
'hard of hearing' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for deaf that I've seen before include "Rudely confident" , "Lacking hearing" , "With impaired hearing" , "Hard of hearing" , "like stone?" .)