Courteous European retaining appeal (6)
I believe the answer is:
polite
'courteous' is the definition.
('polite' can be similar in meaning to 'courteous')
'european retaining appeal' is the wordplay.
'european' becomes 'pole' (Pole is an example**).
'retaining' is an insertion indicator.
'appeal' becomes 'it'.
'pole' going around 'it' is 'POLITE'.
(Other definitions for polite that I've seen before include "Not rude" , "Respectful and considerate" , "Considerate, cultured" , "(Of society) refined" , "Good mannered and civil" .)