French refusal to accept an east European as their ruler (8)
I believe the answer is:
napoleon
'ruler' is the definition.
(I know this)
'french refusal to accept an east european' is the wordplay.
'french refusal' becomes 'non' ('no' in French).
'to accept' indicates putting letters inside.
'an' becomes 'a'.
'east european' becomes 'pole'.
'a'+'pole'='apole'
'non' going around 'apole' is 'NAPOLEON'.
'as their' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
(Other definitions for napoleon that I've seen before include "Old French coin" , "Ex-dictator" , "Gold twenty franc piece" , "French general and emperor" , "The familiar Bonaparte" .)