Women in money match (4)
I believe the answer is:
twin
'match' is the definition.
(twinning is a kind of matching)
'women in money' is the wordplay.
'women' becomes 'w'.
'in' indicates putting letters inside.
'money' becomes 'tin' (I've seen this before**).
'w' placed inside 'tin' is 'TWIN'.
(Other definitions for twin that I've seen before include "Identical sibling" , "Dead ringer" , "One of a similar pair" , "Family member" , "One of two conceived simultaneously" .)