One used to strike for green card (4)
I believe the answer is:
club
This clue is a double definition.
'one used to strike for green' is the first definition.
(a club is used to strike on a golf green)
'card' is the second definition.
(club is a kind of card)
(Other definitions for club that I've seen before include "beat" , "Association of people with similar interests" , "Staff - association" , "In which one could be expecting" , "'Short stick, card suit and association (4)'" .)