Informal wear or undress, also called business wear, corporate/office wear, tenue de ville or dress clothes, is a Western dress code for clothing defined by a business suit for men, and cocktail dress or pant suit for women. On the scale of formality, it is considered less formal than semi-formal wear but more formal than casual wear. Informal or undress should not be confused with casual wear such as business casual or smart casual; most situations calling for “informal wear” will usually tolerate casual dress to varying extents.

Smart casual is an ambiguously defined Western dress code that is generally considered casual wear but with smart components of a proper lounge suit from traditional informal wear. For men, this interpretation typically includes dress shirt, necktie, trousers, and dress shoes, possibly worn with an odd-coloured blazer or a sports coat.