Have us turn against and see off the foreigners (8)
I believe the answer is:
sudanese
'have' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'us turn against and see off the foreigners' is the wordplay.
'turn' shows that the letters should be reversed in order.
'against' means one lot of letters go next to another.
'see off' indicates anagramming the letters.
'the foreigners' becomes 'ese' (I can't explain this - if you can you should give a lot more credence to this answer).
'us' in reverse letter order is 'su'.
'and' with letters rearranged gives 'dan'.
'su'+'dan'+'ese'='SUDANESE'
Can you help me to learn more?
(Other definitions for sudanese that I've seen before include "People in country" , "From Khartoum, perhaps" , "African inhabitants" , "Sue Dean's a native of the African state" , "Africans" .)