n.精神失常；精神病；愚行
It's sheer lunacy driving in this weather. 天气这麽坏还开车，简直是疯了。
Bridge designers had anticipated such lunacy and invented the crossing guard. 吊桥的设计者早就预料到会有这样的精神病穿越吊桥，因而设计了防护装置。
