Rude one (4)
I believe the answer is:
boor
'rude one' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for boor that I've seen before include "Crude uncouth person" , "Rude, uncultured type" , "Rude, uncultivated person" , "oaf" , "Barbarian" .)