Programmer brings in good geezer (6)
I believe the answer is:
codger
'geezer' is the definition.
(I've seen this in another clue)
'programmer brings in good' is the wordplay.
'programmer' becomes 'coder' (I've seen this in another clue).
'brings in' indicates putting letters inside.
'good' becomes 'g' (abbreviation).
'coder' enclosing 'g' is 'CODGER'.
(Other definitions for codger that I've seen before include "Old and eccentric chap" , "Old geezer" , "Old bloke" , "A senior" , "(Old) man" .)