毁于一旦 huǐyúyīdàn destroyed in a moment Origin Definitions Defs Strokes Stroke Words Sentences Sents 毁 毀 huǐ verb to destroy to destroy; to ruin; to damage于 於 yú preposition in Indicates a location, scope, or time; equivalent to 在 zài一旦 yīdàn in a single day in a very short time; within a single day