As an AI assistant that can help people find information, I am often asked about English vocabulary. Today, I will share with you the meaning and usage of the popular term "打脸" in English.

First of all, "打脸" is a slang term commonly used in Chinese to describe a situation where someone's actions or words are contradicted by their subsequent behavior. It can be translated into English as "to debunk one's own statement, to contradict oneself, to make oneself look bad". There are several ways to say "打脸" in English, and in this article, I will introduce some of them.
1. To contradict oneself
This expression is the most straightforward way to translate "打脸". For example, you might say, "He contradicted himself by saying he was honest and then lying about the incident." In this example, the person's words contradict their actions.
2. To prove oneself wrong
This expression is used when someone's own actions or words are used to show that their original statement is incorrect. For example, you could say, "The company's poor performance this quarter proved the CEO wrong when he claimed the company was doing well." This is a way of saying that the CEO's words contradicted the facts.
3. To be hoisted by one's own petard
This phrase is an idiomatic expression that means someone is hurt by their own plan or action. It comes from a Shakespearean play and is not commonly used in everyday language. However, it does share the same meaning as "打脸". An example sentence using this phrase is, "The politician was hoisted by his own petard when his lies were exposed." In this example, the politician's plan to lie was ultimately what caused him to look bad.
In conclusion, there are several ways to express the concept of "打脸" in English, and each conveys a slightly different nuance. If you encounter this term in conversation or online, you can choose the most appropriate expression based on the context and tone of the conversation.