Good man has the old irritation (4)
I believe the answer is:
stye
'irritation' is the definition.
The answer and definition can be both states of affairs as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'good man has the old' is the wordplay.
'good man' becomes 'st' (abbreviation for saint).
'has' says to put letters next to each other.
'the old' becomes 'ye' (resembles a historical spelling of 'the').
'st'+'ye'='STYE'
Can you help me to learn more?
(Other definitions for stye that I've seen before include "makes viewer sore" , "Inflammation around the eye" , "irritation to the viewer" , "Viewer's complaint" , "Eye blemish" .)