Behavior that is not proper or appropriate; something that violates accepted standards of conduct.
From French 'impropriété,' derived from 'improprious' (from Latin 'improbe' meaning dishonest). The 'im-' prefix negates 'propriety,' which means proper conduct.
What counts as 'impropriety' changes dramatically across cultures and centuries—what was scandalous in Victorian England (showing ankles!) is unremarkable today, showing that social standards are invented, not natural.
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