To set out on a journey; to depart; to embark (on a trip).
彼は朝早く故郷を旅立った。
He set off from his hometown early in the morning.
新しい仕事のために来月、家を旅立つ予定だ。
I plan to leave home next month to start a new job.
旅行者たちは夜明けに旅立った。
The travellers departed at dawn.
An euphemism for dying; to pass away (used to gently say someone has died).
祖母は先週静かに旅立った。
My grandmother passed away peacefully last week.
彼は戦友の死を聞いて、深い悲しみの中で旅立ったと語った。
He said his comrade departed amid deep sorrow when he heard the news.