Capital: money stolen by staff (7)
I believe the answer is:
cayenne
'capital' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'money stolen by staff' is the wordplay.
'money' becomes 'yen' (Japanese currency).
'stolen by' means one lot of letters goes inside another.
'staff' becomes 'cane' (I've seen this before).
'yen' inserted into 'cane' is 'CAYENNE'.
Can you help me to learn more?
(Other definitions for cayenne that I've seen before include "South American capital" , "Variety of pepper" , "Kind of pepper" , "Hot red powder" , "Capital of French Guinea" .)