noun, noun or participle which takes 'suru', intransitive verb
staying away overnight; sleepover; spending the night elsewhere
Covers staying overnight at a friend's house, a hotel, or away from one's usual residence. Also used for hospital patients going home for the night. Often used as a suru-verb.
友達の家に外泊する。
I stay overnight at a friend's house.
病院から外泊許可が出た。
I got permission to go home from the hospital for the night.