Business 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, adopted for white-collar workplaces. This interpretation typically including dress shirt and trousers, but worn with an odd-coloured blazer or a sports coat instead. Neck ties are optional in this category.

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.