Republican leader with South African money (4)
I believe the answer is:
rand
'south african money' is the definition.
(currency of South Africa)
'republican leader with' is the wordplay.
'leader' indicates taking the first letters.
'with' becomes 'and'.
The first letter of 'republican' is 'r'.
'r'+'and'='RAND'
(Other definitions for rand that I've seen before include "Foreign currency" , "our 1/4 Across [GOLD MEDALLIST] in 1964" , "Monetary unit in South Africa" , "Currency of South Africa" , "South African money" .)