Brain benign neoplasms are a type of brain tumor that are non-cancerous meaning they do not spread or invade nearby tissues. The opposite of benign is malignant, with malignant tumors being cancerous, rapidly growing, and invasive. Other antonyms for brain benign neoplasms include lethal, harmful, dangerous, critical, and life-threatening. These terms highlight the severity of conditions that differ from a benign tumor. While benign tumors do not directly threaten one's life, they can still cause symptoms, and if left untreated, can eventually grow larger and cause pressure on the surrounding brain tissue, leading to serious complications.