Annoyed fly may be heard (4)
I believe the answer is:
sore
'annoyed' is the definition.
(I've seen this in another clue)
'fly may be heard' is the wordplay.
'fly' becomes 'soar' (soaring is a kind of flying).
'may be heard' shows a homophone (sound like).
'soar' is a homophone of 'SORE'.
(Other definitions for sore that I've seen before include "Hard" , "Tender spot" , "To be very old" , "Eros (anag.)" , "Hurtful to the touch, like rose" .)