Capital account — one that supports credit (5)
I believe the answer is:
accra
'capital' is the definition.
(Accra is an example)
'account one that supports credit' is the wordplay.
'account' becomes 'ac' (abbreviation for account).
'one' becomes 'a'.
'that supports' is a charade indicator (letters next to each other) (bottom letters provide a support for the top ones).
'credit' becomes 'cr'.
'a' put after 'cr' is 'cra'.
'ac'+'cra'='ACCRA'
(Other definitions for accra that I've seen before include "Largest city of Ghana" , "Main city of Ghana" , "foreign capital" , "Ghanaian capital" , "Ghana's capital" .)