Bring down principal European, nonetheless (6)
I believe the answer is:
topple
'bring down' is the definition.
(I've seen this in another clue)
'principal european nonetheless' is the wordplay.
I cannot quite understand how this works, but
'principal' could be 'top' (I've seen this in another clue) and 'top' is found within the answer.
'european' could be 'e' (abbreviation e.g. EU) and 'e' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for topple that I've seen before include "Remove from power" , "Knock (from power?)" , "Overthrow or fall headlong" , "dethroned" , "(Cause to) tip over" .)