To stay behind; to remain after others have left — e.g., staying after class or working overtime.
授業が終わったあと、彼は図書館に居残って勉強した。
After class, he stayed in the library to study.
締め切り前で社員たちは居残って仕事をしている。
With the deadline approaching, employees are staying late to work.
先生に居残りを命じられて、彼は教室に残った。
He was told to stay behind by the teacher, so he remained in the classroom.