Prudery is the behaviour or attitude of people who are too easily shocked by sex, and who often make a point of showing it. It is a critic’s word: you use it when you disapprove. Writers talk about “Victorian prudery” for a time when anything sexual was hidden and judged. The word names the habit, not the person (the person is a prude). It can describe a culture, a law, a school, or a family as well as one face across a table. Like prude, it is about moral tightness around sex and the body, not about saving money or avoiding a crash.