1To feel sadness or sorrow; to grieve, mourn, or regret something. Often used for mourning a death or lamenting a loss or parting.
彼は母の死を深く悲しんでいる。
He is deeply mourning his mother's death.
試験に落ちて、しばらくの間彼女は悲しんでいた。
She was sad for a while after failing the exam.
大切な試合に負けて、チーム全員が悲しんだ。
The whole team was saddened after losing the important match.
友人との別れを悲しむ気持ちを手紙にした。
I wrote a letter expressing how sad I felt about parting with my friend.