Refusal abroad to accept a European emperor (8)
I believe the answer is:
Here is my best explanation:
'emperor' is the definition.
(Napoleon is an example)
'refusal abroad to accept a european' is the wordplay.
'refusal abroad' becomes 'non' (I can't justify this - if you can you should give a lot more credence to this answer).
'to accept' means one lot of letters goes inside another.
'european' becomes 'pole' (Pole is an example).
'non' enclosing 'apole' is 'NAPOLEON'.