To criticize others for a fault you yourself possess; to be hypocritical in your criticism, especially when you share the same flaw.
他自己平时也经常迟到，却总爱对别人指手画脚，真是同浴讥裸。
He himself is often late, yet he always criticizes others; it's a classic case of hypocrisy, like criticizing someone for a flaw you also have.
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