Good man with the old eye problem (4)
I believe the answer is:
stye
'eye problem' is the definition.
(I've seen this before)
'good man with the old' is the wordplay.
'good man' becomes 'st' (abbreviation for saint).
'with' is a charade indicator (letters next to each other).
'the old' becomes 'ye' (resembles a historical spelling of 'the').
'st'+'ye'='STYE'
(Other definitions for stye that I've seen before include "Eyelid problem" , "Inflamed swelling on the edge of an eyelid" , "pain for the observer" , "swelling by organ" , "Ocular affliction" .)