Little shop opening at the retail centre (5)
I believe the answer is:
small
'little' is the definition.
('small' can be a synonym of 'little')
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for small that I've seen before include "Insignificant; young" , "Social chat" , "of little significance" , "Piddling" , "Tiny" .)