Reserve graduate good container (3,3)
I believe the answer is:
ice bag
'container' is the definition.
(ice bag is a kind of container)
'reserve graduate good' is the wordplay.
'reserve' becomes 'ice' (I've seen this before).
'graduate' becomes 'ba'.
'good' becomes 'g' (abbreviation).
'ice'+'ba'+'g'='ICE-BAG'
(Other definitions for ice bag that I've seen before include "Waterproof container" , "Cold item applied to reduce swelling" , "cooler" , "Chilled sack applied to swellings, etc" , "Container for diamonds, or cold cubes to stop swelling" .)