Machismo shown by island's housing policies (9)
I believe the answer is:
Here is my best explanation:
'machismo' is the definition.
The answer and definition can be both human attributes as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'island's housing policies' is the wordplay.
'island's' becomes 'mans' (Man is an example).
'housing' means one lot of letters goes inside another.
'policies' becomes 'lines' (as in a party line, a political policy or view).
'mans' enclosing 'lines' is 'MANLINESS'.
'shown by' acts as a link.