Civil European accepts it (6)
I believe the answer is:
polite
'civil' is the definition.
(synonyms)
'european accepts it' is the wordplay.
'european' becomes 'pole' (someone from Poland).
'accepts' is an insertion indicator.
'pole' enclosing 'it' is 'POLITE'.
(Other definitions for polite that I've seen before include "Well mannered" , "Well-mannered, courteous" , "Cultivated" , "Minding one's p's and q's" , "(Of society) refined" .)