It houses a money-making enterprise (4)
I believe the answer is:
mint
'it houses a' is the definition.
The definition suggests a singular noun which matches the answer.
'money-making enterprise' is the wordplay.
'money' becomes 'm' (abbreviation used in economics).
'making enterprise' becomes 'int' (I am not sure about this - if you are sure you should believe this answer much more).
'm'+'int'='MINT'
Can you help me to learn more?
(Other definitions for mint that I've seen before include "lots of money" , "Coin-making place or nice lamb sauce" , "Grown in the herb garden" , "Plant - in perfect condition" , "sweet > factory?" .)