Shopping centre entirely chasing millions (4)
I believe the answer is:
mall
'shopping centre' is the definition.
(I've seen this before)
'entirely chasing millions' is the wordplay.
'entirely' becomes 'all' (I've seen this before).
'chasing' is a charade indicator (letters next to each other).
'millions' becomes 'm' (abbreviation).
'all' after 'm' is 'MALL'.
(Other definitions for mall that I've seen before include "Public walk" , "Shopping precinct" , "Sheltered walk or promenade" , "Pedestrian shopping area" , "Mercantile centre" .)