Working, attached to Irish golf club (4)
I believe the answer is:
iron
'golf club' is the definition.
(I've seen this before)
'working attached to irish' is the wordplay.
'working' becomes 'on'.
'attached to' is a charade indicator (letters next to each other).
'irish' becomes 'ir' (abbreviation).
'on' after 'ir' is 'IRON'.
(Other definitions for iron that I've seen before include "Magnetic metallic element" , "Heavy metal that rusts easily" , "The one who was 'not for turning'" , "Ferrous metal" , "great strength" .)