Demote European envoy after resistance (8)
I believe the answer is:
relegate
'demote' is the definition.
('relegate' can be a synonym of 'demote')
'european envoy after resistance' is the wordplay.
'european' becomes 'e' (abbreviation e.g. EU).
'envoy' becomes 'legate' (legate is a kind of envoy).
'after' is a charade indicator (letters next to each other).
'resistance' becomes 'r' (abbreviation).
'e'+'legate'='elegate'
'elegate' put after 'r' is 'RELEGATE'.
(Other definitions for relegate that I've seen before include "Downgrade" , "Put in a lower division" , "Send down" , "Transfer to a lower division" , "Move down to a lower grade" .)