Part of conditional release the old man ignored (4)
I believe the answer is:
role
'part' is the definition.
('role' can be a synonym of 'part')
'conditional release the old man ignored' is the wordplay.
'conditional release' becomes 'parole' (I've seen this before).
'the old man' becomes 'pa' ('pa' can be a synonym of 'old man').
'ignored' indicates named letters should be taken away.
'parole' with 'pa' removed is 'ROLE'.
'of' acts as a link.
(Other definitions for role that I've seen before include "A part of lore" , "Function; part" , "Part played (in life?)" , "Playing part" , "Acting part" .)