• Basic forms
• 悲しむ — to feel sad; to grieve / base form
• 悲しみます — (I) feel sad / masu form
• 悲しんだ — felt sad; grieved / ta form
• 悲しんで — feeling sad; grieving / te form
• 悲しまない — do not feel sad / negative
• 悲しめば — if (someone) feels sad / conditional
• 悲しめ — be sad! (rare) / imperative
• Other common forms
• 悲しみたい — want to grieve (rare) / want to
• 悲しめる — can feel sad (rare) / potential
• 悲しめなかった — couldn’t grieve / negative potential
• More
• 悲しもう — let’s grieve / volitional
• 悲しまなかった — did not feel sad / negative past
• 悲しんでいる — is grieving; is feeling sad / progressive

悲しむ（かなしむ） is a godan verb. It expresses emotional sadness or grief, often used for events that cause pain or disappointment (e.g., 人の死を悲しむ).