Prim, self-righteous (8)
I believe the answer is:
priggish
I believe this clue is a double definition.
'prim' is the first definition.
(synonyms)
'self-righteous' is the second definition.
(I've seen this before)
(Other definitions for priggish that I've seen before include "Self-righteously superior" , "Strait-laced" , "smug" , "Sanctimonious" , "Self-righteously moralistic" .)