众人皆知 zhòng rén jiē zhī
司马昭之心，路人皆知 Sīmǎ Zhāo zhī xīn,lùrén jiē zhī[Sima Zhao's ill intention is obvious to everybody in the street;the trick is all too evident to the man in the street] 《三国志·魏志·高贵乡公纪》裴松之注引《汉晋春秋》记载,魏帝曹髦在位时,大将军司马昭,独揽大权,图谋篡位,曹髦一次气愤地对大臣说:“司马昭之心,路人所知也。吾不能坐受废辱,今日当与卿自去讨贼。”后用“司马昭之心,路人皆知”比喻人所共知的阴谋、野心