Jiang Lang has exhausted his talent
This is used to indicate that one's intellect or ability has faded
Neutral
在文学创作上他已是江郎才尽了 | Zài wénxué chuàngzuò shàng tā yǐ shì jiānglángcáijìn le
In terms of writing, he's already exhausted his talents
[Source]
这几位作家久未有作品问世，是否已经江郎才尽？ | Zhè jǐ wèi zuòjiā jiǔwèi yǒu zuòpǐn wènshì, shìfǒu yǐjīng jiānglángcáijìn?
These authors haven't released any work in a long time. Could it be that their talents have dried up?
[Source]
To exhaust one's talents
To have one's talents dry up
江淹才尽 (Jiāng Yán cái jìn)
江郎 (Jiāng Láng) was also known as 江淹 (Jiāng Yán), hence the variation of this chengyu
《南史》(Nán Shǐ), a work by 李大师 (Lǐ Dà Shī) and his son 李延寿 (Lǐ Yán Shòu). The work covers the history of the four Southern Dynasties (宋, 齐, 梁, and 陈) and is generally known in English as "History of the Southern Dynasties."
During the Southern Dynasties (南朝, Nán Cháo, 420 - 589) there lived a man named 江郎 (Jiāng Láng). In his youth, 江郎's family was deeply impoverished, and he studied extremely hard so that he could become a government official. It quickly became apparent that he possessed great talent for writing and drawing, and after some time, these skills allowed him to realize his goal. However, as he grew older, his talent seemed to evaporate, and no matter how hard he tried, he couldn't produce any decent content. A rumor eventually spread to explain this unfortunate turn of events. According to the rumor, one day when 江郎 was sleeping during a trip on a boat, the image of the writer and philosopher 郭璞 (Guō Pú) appeared before him and said, "You've had my brush for a long time, and it's time you give it back to me." 江郎 patted his chest until he found the brush in question, then handed it over to 郭璞. And, from that very moment, 江郎 was unable to produce any notable works.