ADJ. only before noun, existing, happening, or used outside, not inside a building.
ADV. If something happens outdoors, it happens outside in the fresh air rather than in a building.
- It was warm enough to be outdoors all afternoon.
N-SING You refer to the outdoors when talking about activities that take place outside away from buildings. 户外活动 I’m a lover of the outdoors. 我是个户外活动爱好者。