Sleeping outdoors; spending the night out in the open (often without formal lodging or a tent).
夜行列車が運休になり、駅で野宿する人がいた。
The night train was canceled, and some people ended up sleeping outdoors at the station.
山で道に迷ってしまい、仕方なく野宿した。
We got lost in the mountains and had no choice but to sleep outdoors.
野宿は防寒対策が不十分だと危険なので、準備をしっかりする必要がある。
Sleeping outdoors can be dangerous if you don't have proper cold-weather gear, so you need to prepare carefully.