A crane standing in a flock of chicken
When a person's appearance or intellect makes them stand out amongst their peers
Positive
他衣冠楚楚，在俱乐部中如鹤立鸡群 | Tā yīguānchǔchǔ, zài jùlèbù zhōng rú hèlìjīqún
He was so impeccably dressed that he stood out inside the night club
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这篇文章在所有参赛作品中，鹤立鸡群，真是出色 | Zhè piān wénzhāng zài suǒyǒu cānsài zuòpǐn zhōng, hèlìjīqún, zhēnshi chūsè
This article stands out among all the entries for this competition. It's really outstanding
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Stand out from the crowd
None
Careful — this is NOT the same thing as "stick out like a sore thumb." That English idiom has a negative connotation, while this chengyu has a positive one
《世说新语》(Shì Shuō Xīn Yǔ) by southern Sòng Dynasy (南宋, 1127 - 1279) writer 刘义庆 (Liú Yì Qìng). Known in English as "A New Account of the Tales of the World,"《世说新语》is a collection of anecdotes, conversations, and remarks on historic personalities
嵇绍 (Jī Shào) was an imperial aide during the Jìn Dynasty (晋, 265 - 420). He was a remarkably intelligent man, and he was also big and strong, so he easily stood out among his peers.
In addition, 嵇绍 was an extremely loyal man. The emperor at the time faced an immense power struggle as members of his household fought and killed each other to gain control over his throne, but amidst all the violence and destruction, 嵇绍 stayed by the emperor's side. When the city later fell into chaos, 嵇绍 even followed the emperor and his deployed troops into battle. Unfortunately, the emperor's forces were defeated, and 嵇绍 was deeply injured. It was there on the battlefield, bleeding into the emperor's robes, that he passed away.
Many people were deeply moved when they heard of 嵇绍's loyalty, and they told the devastated and grieving emperor that his aide had truly been "a crane standing a flock of chickens."