Crude newspaper; Liberal, upper-class, very revolting (6)
I believe the answer is:
vulgar
'crude' is the definition.
(I know that crude can be written as vulgar)
'newspaper liberal upper-class very revolting' is the wordplay.
'newspaper' becomes 'rag' (informal term for a newspaper).
'liberal' becomes 'l' (abbreviation).
'upper-class' becomes 'u' (similar in meaning).
'very' becomes 'v' (abbreviation).
'revolting' says the letters should be written in reverse.
'rag'+'l'+'u'+'v'='ragluv'
'ragluv' written backwards gives 'VULGAR'.
(Other definitions for vulgar that I've seen before include "Coarse or ribald" , "Coarse, boorish" , "Indecent" , "Common, tasteless" , "Lacking in good taste" .)