strait-laced

This term carries a strong connotation of rigidity and social repression. It describes individuals or institutions that adhere to a strict, often outdated, moral code, viewing any deviation from conventional behavior as improper or scandalous. While it can be used neutrally to describe a disciplined person, it is more frequently used as a mild criticism to imply that someone is prudish, humorless, or overly concerned with propriety.

In modern usage, the word often evokes an image of Victorian-era social constraints. It is distinct from being simply "conservative" or "traditional," as it specifically emphasizes the restrictive and formal nature of the behavior, suggesting a lack of flexibility or openness to new ideas.