Abstract: From Word and Expression, we can find that the word “man” has the meaning of “droopy eyelids”. Therefore, we can infer from CAO Cao's nick name “A Man” that his eyelids might be droopy. In The Romance of Three Kingdoms, he is described as a man who has small eyes and long beard. In drama, CAO's facial makeup is characterized by “staring”. Before Tang Dynasty, the name “A Man” was derogatory when it was not harmonious with the situation. After Song Dynasty, the word “man” began to take the meaning of “deception or lie”. Ever since then, such meaning has hardly been used. However, the names “A Man” and “CAO Man” has become quite usual. People have related the new meaning of “man” with the deceptive and foxy characters to CAO Cao, hence we can understand what the name CAO Man means. This is just in accordance to people's inclination of supporting LIU Bei and opposing CAO after Song Dynasty. People have used such names to criticize his killing of MI Heng, KONG Rong, YANG Xiu and scandals of defeat in Chibi and Tongquetai.