Prison fridge? (6)
I believe the answer is:
cooler
I believe this is a double definition.
'prison' is the first definition.
(informal term for a prison)
'fridge?' is the second definition.
(something which keeps food cool)
(Other definitions for cooler that I've seen before include "It's not so hot" , "Nick" , "Fan" , "more sophisticated" , "less enthusiastic" .)