Break one's promise
      

Do you need a Chinese saying to describe someone who breaks a promise? If so, check out this Chinese idiom.

To get fat on eating one's own words — Break one's promise.

Meng Wubo was the prime minister of the State of Lu during the Spring and Autumn Period, about 2,500 years ago. He always went back on his word. So Duke Ai of Lu was very dissatisfied with him.

One day, Duke Ai came back from the State of Yue, and Meng Wubo and another official, Ji Kangzi went to Wuwu to meet him. Guo Zhong, a senior official was accompanying Ai on his visit. He was highly regarded by the duke, so Meng Wubo was very jealous of him. After meeting Meng Wubo and Ji Kangzi, Guo Zhong reported to Duke Ai, "The two men spoke ill of you. Please be careful."

But Duke Ai honored Meng Wubo and Ji Kangzi at a banquet. Guo Zhong was also invited. Meng Wubo proposed a toast to Guo Zhong, just to tease him. He asked Guo, "How come you"ve put on so much weight?"

Ji Kangzi butted in, "We should punish Meng Wubo. Guo Zhong worked so hard to accompany the duke on his visit to the State of Yue. How can you say he is putting on weight?"

Duke Ai darted a glance at Ji Kangzi and Meng Wubo, and said, "This is because he eats too many words. How could he not become fat?" In Chinese, "eat words" means "go back on one"s word." This put Meng and Ji in a very bad mood. They left in a huff. From then on, there was discord between Duke Ai and the two officials.

From what Duke Ai said about Guo Zhong, people get the idiom Shi Yan Er Fei. Now the phrase is used to mock someone who fails to keep his promise.