Transitive verb and Godan verb
かなしむ
かの女は失れんしてとても悲しんでいます。
She got dumped and she's very sad.
人間だけではなく、動物も仲間の死を悲しみます。
Animals, as well as humans, are saddened by the deaths of their friends.
そう悲しむなって。お前の日本語は今はそれで十分だよ。ただ、勉強することを投げ出さずに、少しずつ上手くなればいいさ。
Don’t be sad. Your Japanese is good enough for now. Just don’t stop learning and you’ll improve little by little.
This word consists of kanji with hiragana attached. Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means sad so the verb form of that is to be sad. Boohoo.
If you're going to be sad about something right now, it will be kana (かな). Don't use kana when you're trying to learn kanji! You'll be sad forever if you're stuck using kana your whole life, so don't let that habit start now, friend.