Calendar girl returning container (7)
I believe the answer is:
almanac
'calendar' is the definition.
(I've seen this before)
'girl returning container' is the wordplay.
'girl' becomes 'alma' (girl's name).
'returning' shows that the letters should be reversed in order.
'container' becomes 'can' (can is a kind of container).
'can' reversed gives 'nac'.
'alma'+'nac'='ALMANAC'
(Other definitions for almanac that I've seen before include "Annual publication with mixed data, forecasts etc." , "Annual publication providing information like Old Moore's" , "Annual containing information, Old Moore's say" , "Statistical calendar" , "Kind of year-book like Old Moore's" .)