老气横秋 old-fashioned and self-important
Explanation
形容老练而自负的神态。现形容自高自大，摆老资格。也形容缺乏朝气。
To describe the self-important and condescending manner of an old person. Now it describes being arrogant and showing off one's seniority. It also describes a lack of vitality.
Origin Story
话说南朝时期，有个老秀才，名叫王老汉，自诩饱读诗书，见多识广。一日，他去拜访一位年轻的学者，本想显摆一下自己的学识，却发现年轻学者对时事和新学问的理解远超自己。王老汉心中不服气，便老气横秋地批评年轻学者不懂传统，只知新潮。年轻学者不卑不亢地与他辩论，最终以理服人，让王老汉自觉无地自容。
In the Southern Dynasties, there was an old scholar named Wang Lao, who considered himself knowledgeable and widely read. One day, he went to visit a young scholar. He wanted to show off his knowledge, but he found that the young scholar's understanding of current events and new knowledge far exceeded his own. Wang Lao was unconvinced and condescendingly criticized the young scholar for not understanding tradition and only knowing new trends. The young scholar argued calmly and rationally, finally winning the argument and leaving Wang Lao ashamed.
Usage
用于形容人自高自大，摆老资格，或者缺乏朝气。
Used to describe someone who is arrogant, showing off their seniority, or lacking vitality.
Examples
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他说话老气横秋的，让人很不舒服。
tā shuōhuà lǎoqì héngqiū de, ràng rén hěn bù shūfu。
His words were full of condescending air, making people very uncomfortable.
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年轻人不要老气横秋，要多学习，多进步。
niánqīng rén bùyào lǎoqì héngqiū, yào duō xuéxí, duō jìnbù。
Young people should not be old-fashioned and self-important; they should learn more and make progress