expression, ichidan verb
risk one's life; put one's life on the line; give one's all
Used both literally (life-threatening risk) and figuratively (putting everything into an effort).
消防士は命を懸けて人を助ける。
Firefighters risk their lives to save people.
彼は命を懸けてそのプロジェクトに取り組んだ。
He put everything he had into that project.