State seizing Grand Duke settled abroad (9)
I believe the answer is:
emigrated
'settled abroad' is the definition.
'state seizing grand duke' is the wordplay.
'state' becomes 'emirate' (I've seen this before**).
'seizing' is an insertion indicator.
'grand' becomes 'g' ('G' can be a synonym of 'grand').
'duke' becomes 'd'.
'emirate' going around 'g' is 'emigrate'.
'emigrate'+'d'='EMIGRATED'
(Other definitions for emigrated that I've seen before include "Went abroad to live" , "moved overseas" , "Moved abroad" , "gone away?" .)