Common, crude (6)
I believe the answer is:
vulgar
This clue is a double definition.
'common' is the first definition.
(I know that common can be written as vulgar)
'crude' is the second definition.
(I know that crude can be written as vulgar)
(Other definitions for vulgar that I've seen before include "Coarse and common" , "Common, tasteless" , "Lacking refinement, culture or taste" , "Coarse, lacking refinement" , "Coarse and uncouth" .)