What does 언중유골(言中有骨) really mean?

언중유골(言中有骨) is used to refer to language that contains an implied or hidden meaning, which is usually sarcastic or critical. The literal meaning is "There is a bone in the middle of the words." Here are the individual characters:

• 言(언) speech
• 中(중) middle
• 有(유) exist
• 骨(골) bone

Since first learning this saying, I had always been curious about the expression 有骨(유골). I had always wondered why there was a "bone" in the words, and not something else? Well, today I came across another expression that also has 有骨(유골) in it, and now I think I understand its real meaning.

Today I came across the saying 鷄卵有骨(계란유골), which literally means, "There is a bone in the egg." The expression is used to refer to an event where the luck of a normally unlucky person seems to be changing, but ends up being a continuation of the same bad luck. Here is the story behind the expression:

황희(黃喜) was a Choseon Dynasty prime minister during King Sejong's reign. He lived an honest and simple life, and was very poor. The roof of his house leaked, and he had only one set of court robes.

King Sejong felt sorry for 황희 and decided one day to help him. The king told him that he could go to South Gate market the next day and buy for himself all the goods that came in that day. Unfortunately, there was a big rain storm all day the next day and no merchants came to the market, except one old man carrying a bundle of eggs. 황희 bought the eggs and carried them back home. Later when he tried to cook the eggs, he discovered that they were all rotten.

In Korean, a rotten egg is called 곯은 달걀, and according to this site, because 곯 and 골(骨) have the same sound, Koreans used the Chinese character 골(骨) to represent 곯 in writting. Therefore, 鷄卵有骨(계란유골) actually means, "The eggs are rotten."

If 유골(有骨) means "rotten," then the intended meaning of 언중유골(言中有骨) would be, "Among the words, some are rotten."