More impolite (5)
I believe the answer is:
ruder
'more impolite' is the definition.
('rude' can be similar in meaning to 'impolite')
This is all the clue.
(Other definitions for ruder that I've seen before include "more robust" , "less pleasant in manner" , "Coarser" , "Less polite" , "comparatively unsophisticated" .)