noun, noun or participle which takes 'suru', intransitive verb
A long, deep sigh, often expressing relief, exhaustion, or deep emotion. Can be used as a noun or with する to mean 'to heave a deep sigh'.
彼は長大息をついて、椅子に深く座り直した。
He heaved a deep sigh and sat back deeply in his chair.
試
When the exam was over, I let out a deep sigh without thinking.