What time will husband return new boxes? (4)
I believe the answer is:
when
'what time' is the definition.
(thesaurus)
'husband return new boxes?' is the wordplay.
'husband' becomes 'h' (abbreviation).
'return' is a reversal indicator.
'boxes?' indicates putting letters inside (the outside letters must 'box' inside letters in).
'new' reversed gives 'wen'.
'h' placed into 'wen' is 'WHEN'.
'will' is the link.
(Other definitions for when that I've seen before include "Say it when you''ve had enough" , "stop pouring the drink" , "At what time?" , "As soon as" , "Over what period?" .)