Government contribution to Mexican doctor (6,3)
I believe the answer is:
income tax
'government contribution' is the definition.
The answer and definition can be both related to property as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'to mexican doctor' is the wordplay.
'doctor' is an anagram indicator.
'to'+'mexican'='tomexican'
'tomexican' anagrammed gives 'INCOME-TAX'.
Can you help me to learn more?
(Other definitions for income tax that I've seen before include "not what one takes home?" , "What must be paid following return" , "Part of earnings lost?" , "state levy" , "Form of exaction" .)