Everyone supports motorway shopping centre (4)
I believe the answer is:
mall
'shopping centre' is the definition.
(I've seen this before)
'everyone supports motorway' is the wordplay.
'everyone' becomes 'all' (I've seen this before).
'supports' is a charade indicator (letters next to each other) (bottom letters provide a support for the top ones).
'motorway' becomes 'm'.
'all' put after 'm' is 'MALL'.
(Other definitions for mall that I've seen before include "Public walk" , "Sheltered walk or promenade" , "Covered complex of shops or path by a canal" , "Mercantile centre" , "Shopping area closed to vehicles" .)