outer garment; overgarment
Refers to a garment worn over other clothes, such as a coat, jacket, or outer layer. Not as common as 上着 (うわぎ) in everyday speech, but understood.
It's cold, so I'll go out wearing an outer garment.
This outer garment is light and warm.
Compound of 上 (うわ, 'upper') and 服 (ふく, 'clothing'). The reading うわふく follows standard rendaku patterns.