a goody two shoes
A goody two shoes is a super annoying person who thinks they're perfect and always does the right thing, like they’re not human.
My goody two shoes friend never even eats pizza and would rather die than get in trouble.
My goody two shoes neighbor wears a bra to school and thinks everyone else is a sinner.
My goody two shoes sister lectures me about my ‘sinful’ lifestyle every Sunday.