Key for cupboard? (6)
I believe the answer is:
locker
I believe this is a double definition.
'key' is the first definition.
(I've seen this before)
'cupboard?' is the second definition.
(I've seen this before)
'for' is the link.
(Other definitions for locker that I've seen before include "Chest on board ship" , "Storage compartment" , "Box" , "Small cupboard for personal use" , "Small compartment where things can be securely stored" .)