典出《圣經·舊約·但以理書》第 2 章。巴比倫國王尼布甲尼撒(Nebuchadnezzar)夢到一泥足巨人,頭是金的,胸臂是銀的,腹股是銅的,被飛來的一塊巨石砸碎了腳,整個巨人頓時瓦解。希伯來先知但以理釋夢稱這預示著國家要分裂。現多用來指"偉人不為人知的弱點或致命的弱點"。
Eg.When the coach was arrested for drunken driving, the students realized that their hero had feet of clay.
當教練酒后駕駛被拘留,學生們才意識到他們心目中的英雄也有致命的弱點。