State seizing Grand Duke settled abroad (9)
I believe the answer is:
Here is my best explanation:
'settled abroad' is the definition.
'state seizing grand duke' is the subsidiary indication.
'state' becomes 'emirate' (**).
'seizing' means one lot of letters goes inside another.
'grand' becomes 'g' ('G' can be a synonym of 'grand').
'duke' becomes 'd'.
'emirate' placed around 'g' is 'emigrate'.
(Another definition for emigrated that I've seen is "Went abroad to live".)