Small advance by one member in workplace (4)
I believe the answer is:
shop
'workplace' is the definition.
(I know that shop is a type of workplace)
'small advance by one member' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'advance by one member' becomes 'hop' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
's'+'hop'='SHOP'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for shop that I've seen before include "Place to buy" , "Retail outlet" , "Betray - place selling things" , "Be disloyal to" , "sales outlet" .)