Refinement of manners and language (6)
I believe the answer is:
polish
I believe this clue is a double definition.
'refinement of manners' is the first definition.
(I've seen this before)
'language' is the second definition.
(Polish is an example)
'and' acts as a link.
(Other definitions for polish that I've seen before include "make things shiny" , "Substance used to produce shine" , "Brush up" , "Rub to a gloss" , "European - gloss" .)