Device containing spring cabbage maybe left around for rabbit to eat (4,4)
I believe the answer is:
yale lock
'device containing spring' is the definition.
'cabbage maybe left around for rabbit to eat' is the wordplay.
'cabbage maybe' becomes 'cole' (cabbage is a type of cole).
'left' becomes 'l' (common abbreviation).
'around' is a reversal indicator.
'for rabbit' becomes 'yak' (I am not sure about this - if you are sure you should believe this answer much more).
'to eat' indicates putting letters inside.
'cole'+'l'='colel'
'colel' reversed gives 'leloc'.
'leloc' put within 'yak' is 'YALE LOCK'.
(Other definitions for yale lock that I've seen before include "that restricts entry" , "security" , "One may secure entrance" , "piece with unique key" .)