adj. Pretending to be righteous
My sanctimonious friend looks down upon people who cheat, but she passed History last year by copying someone else's answers.
Valerie is a sanctimonious girl who talks condescendingly to people who don't volunteer, but she has never volunteered outside of the required hours for school.
Synonyms: pious, self-righteous, preachy
Antonyms: humble, meek, modest