Move abroad to oust grand government (7)
I believe the answer is:
emirate
'government' is the definition.
(I have seen 'Muslim government' mean 'emirate' so perhaps 'government' could also mean 'emirate')
'move abroad to oust grand' is the wordplay.
'move abroad' becomes 'emigrate' (I've seen this before).
'to oust' is a deletion indicator.
'grand' becomes 'g' (G is short for grand as in a thousand).
'emigrate' with 'g' removed is 'EMIRATE'.
(Other definitions for emirate that I've seen before include "A Middle East office" , "Muslim country, such as Kuwait" , "Muslim government" , "Such as Abu Dhabi or Dubai" , "Islamic office" .)