Irregular money in South Africa doctor raised (6)
I believe the answer is:
random
'irregular' is the definition.
(I've seen this before)
'money in south africa doctor raised' is the wordplay.
'money in south africa' becomes 'rand' (South African currency).
'doctor' becomes 'mo' (medical officer).
'raised' says the letters should be written backwards.
'mo' back-to-front is 'om'.
'rand'+'om'='RANDOM'
(Other definitions for random that I've seen before include "Following no method" , "Roderick came before it" , "Chance, irregular" , "Unsystematic" , "Without a particular aim or purpose - say a choice" .)