Civil (6)
I believe the answer is:
polite
'civil' is the definition.
(I know that civil can be written as polite)
This is the entire clue.
(Other definitions for polite that I've seen before include "Considerate, cultured" , "Good mannered and civil" , "Cultured, refined" , "Not rude" , "Minding one's p's and q's" .)