goody two shoes
noun
• an ostentatiously virtuous or well-behaved person.
• "she was such a goody two shoes"
Origin:
mid 18th-century: from the nickname of the heroine of History of Little Goody Two-shoes (1766), a popular children's story in which an orphan girl triumphs over adversity through her unwavering virtue and hard work to become a teacher and marry a rich man, using her new-found wealth to help the poor and do good works.
