To change colors at the mention of a tiger
To become frightened at the mere mention of something terrible, so much so that one's face even goes pale
Negative
一提起癌，人们便谈虎色变 | Yī tíqǐ ái, rénmen biàn tánhǔsèbiàn
People turn pale at the mention of cancer
[Source]
经历过唐山大地震的同志说起地震来马上就谈虎色变 | Jīnglìguò tángshān dà dìzhèn de tóngzhì shuō qǐ dìzhèn lái mǎshàng jiù tánhǔsèbiàn
Comrades who experienced the Great Tangshan Earthquake [of 1976] immediately turn pale at discussion of earthquakes
[Source]
None
None
The brothers mentioned in the story were scholars. Their combined ideas were further developed by 朱熹 (Zhū Xī), who would go on to found neo-Confucianism
《二程全书》(Èr chéng quán shū), a work of philosophy composed by the Sòng Dynasty (宋, 960 - 1279) scholars 程颢 (Chéng Hào) and 程颐 (Chéng Yí)
During the Sòng Dynasty (宋, 960 - 1279), there lived two brothers named 程颐 (Chéng Yí) and 程颢 (Chéng Hào). One day, the elder brother 程颐 was explaining to a group of people an experience he had once had. He and some friends had been chatting, and someone had mentioned that a tiger had harmed a not insignificant amount of people in a nearby village. Most of the friends had been horrified by the news, but one person grew exceptionally pale. It turned out that this person had previously been bitten by a tiger himself, and the story had reminded him of his previous injury.