Couple in white married (4)
I believe the answer is:
item
'couple' is the definition.
(a romantic couple are 'an item')
'in white married' is the wordplay.
'in' says the answer is hidden in the clue.
'ITEM' can be found hidden inside 'white married'.
(Other definitions for item that I've seen before include "Matter" , "Individual object" , "Two lovers as one" , "Separate article" , "Boyfriend and girlfriend" .)