‘外衣’ literally means ‘outer clothing’—‘外’ (wài) means ‘outside’ or ‘external’, and ‘衣’ (yī) means ‘clothing’ or ‘garment’. Together, they refer to any piece of clothing worn over other clothes for warmth, protection, or style—such as coats, jackets, blazers, or trench coats. Unlike more specific terms like ‘大衣’ (dàyī, overcoat) or ‘夹克’ (jiākè, jacket), ‘外衣’ is a general, neutral term used in everyday speech and writing.

This word emphasizes function and layering: it’s the topmost garment you put on before going outdoors or into cooler environments. It’s commonly used in weather-related contexts (e.g., ‘天气变冷了，记得穿外衣’), fashion advice, and health-related reminders (e.g., ‘感冒时要多穿外衣’). While it can occasionally refer metaphorically to a ‘public persona’ (as in ‘他总用幽默作外衣’), that usage is literary and rare for beginners.