Money expert in club (4)
I believe the answer is:
mace
'club' is the definition.
(I've seen this before)
'money expert' is the wordplay.
'money' becomes 'm' (abbreviation in economics**).
'expert' becomes 'ace' (ace is a kind of expert).
'm'+'ace'='MACE'
'in' acts as a link.
(Other definitions for mace that I've seen before include "Came to get nutmeg spice" , "Ceremonial staff of office" , "Came to get ancient weapon" , "Staff of office for a flavouring" , "Spiked club" .)