暴虎冯河 bàohǔ-pínghé

[brash physical courage;attack a tiger unarmed and cross a river without a boat] 赤手空拳打老虎,没有渡船要过河。比喻有勇无谋,冒险蛮干(暴虎:空手打虎;冯河:徒步渡河)

不敢暴虎,不敢冯河。——《诗·小雅》