风吹草动 Every rustle and stir
Explanation
风一吹，草就动。比喻轻微的变动或迹象。
The wind blows, and the grass moves. A metaphor for slight changes or signs.
Origin Story
春秋时期，楚国权臣子常为了讨好昏庸的楚平王，竟然将他自己的儿媳妇献给了楚平王。太子少傅伍奢看不惯楚平王的荒淫无道，挺身而出，直言进谏。结果，楚平王勃然大怒，将伍奢下狱。为了斩草除根，楚平王又派人去抓捕伍奢远在外的两个儿子伍尚和伍员（即伍子胥）。伍尚不幸落入圈套，被杀害。伍员在逃亡途中，时刻警惕风吹草动，他深知楚国权势熏天，自己若稍有疏忽，便可能命丧黄泉。他白天潜伏，夜晚赶路，躲避追兵，历尽艰辛，终于逃到了吴国。在吴国，他得到重用，后来帮助吴王阖庐打败楚国，为父兄报仇雪恨，最终成为一代名臣。
During the Spring and Autumn period, a powerful minister of Chu, Zichang, to please the capricious King Ping of Chu, actually offered his own daughter-in-law to King Ping of Chu. The crown prince's tutor, Wushe, could not bear to see King Ping of Chu's debauchery and unprincipled conduct and stood up to advise him. As a result, King Ping of Chu was furious and imprisoned Wushe. In order to eliminate the threat entirely, King Ping of Chu sent people to arrest Wushe's two sons, Wushang and Wu Yuan (also known as Wu Zixu), who were far away. Wushang unfortunately fell into a trap and was killed. Wu Yuan, during his escape, remained constantly vigilant, keenly aware of even the slightest sign of danger. He knew that the power of Chu was overwhelming, and any carelessness would mean his death. He hid during the day, traveled at night, and evaded pursuers, ultimately enduring hardship to reach Wu. In Wu, he was highly valued, later helping King Helu of Wu defeat Chu and avenge his father and brother, eventually becoming a famous minister.
Usage
多用于比喻句中，形容细微的变动。
Often used in metaphors to describe subtle changes.
Examples
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山雨欲来风满楼，这风吹草动，是不是有什么大事要发生？
shan yu yu lai feng man lou, zhe feng chui cao dong, shi bushi you shenme da shi yao fashi?
The wind is blowing and the grass is moving. Is something big about to happen?
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他做事非常谨慎，生怕风吹草动，影响全局。
ta zuo shi fei chang jin shen, sheng pa feng chui cao dong, yingxiang quanju
He is very cautious in his work, lest any small event affect the overall situation.