During the Northern Wei Dynasty, there was a Hui man named Feng Gui. He was cautious and reserved, loved learning, and had a particular expertise in Confucian classics. He and Grand Master of Splendor Sun Huiwei shared the same ideals and were close friends. Whenever Sun Huiwei met him, he would always praise him, saying, "Your understanding of the Confucian scriptures truly surpasses my own."
Feng Gui was a man of integrity who refused to flatter the powerful. At the time, a renowned scholar named Gao Chuo invited Feng Gui to pay respects to Gao Zhao, the brother of Empress Dowager Wenzhao, who had become a minister. Gao Zhao was notorious for cronyism—"those who flattered him rose quickly, while those who opposed him faced ruin"—and Feng Gui despised him, so he declined. When Gao Chuo noticed Feng Gui's absence at Gao Zhao's residence, he rushed back and remarked, "I always prided myself on having the integrity of a scholar who doesn't grovel to the mighty. But today I realize how far I fall short of Feng Gui!"
Feng Gui was handsome in appearance, tall in stature, and always paid great attention to grooming. A slovenly scholar asked him, "Most scholars don't care about their appearance. You are a learned man—why are you so particular about this?"
Feng Gui laughed and said to that person, "A person of good character wears his hat straight, dresses neatly, and maintains proper demeanor when looking at people and things. Why must one have disheveled hair and a dirty face to be considered a worthy person?"
The man was left speechless by his words and walked away in shame.
Later, the idiom "disheveled and unkempt" came to describe someone with messy hair and a dirty face.
Source: *Book of Wei*, "Biography of Feng Gui"
Meaning of the Idiom: Later, the Chinese idiom "蓬头垢面" came to describe how someone with messy hair and a dirty face.