Kong Rong was a famous writer of the late Eastern Han Dynasty. As a child, he was very intelligent and polite, and the story of "Kong Rong Giving Away Pears" is known in almost every household.
At ten years old, Kong Rong followed his father to Luoyang, where the governor Li Yuanli was a towering figure—only his closest friends and the era's most celebrated scholars could step through his gates.
When the young Kong Rong heard about Li Yuanli, he decided to pay him a visit. Arriving at Li's gate, he announced boldly, "I am a relative of Governor Li—please announce me." The guard led him to the main hall, where Li Yuanli, seeing an unfamiliar child, asked in surprise, "I don't know you. How exactly are we related?" Kong Rong replied, "Our families have been friends for generations. My name is Kong Rong."
Li Yuanli was utterly confused, unable to recall having any relative surnamed Kong. Kong Rong explained calmly, "I am the twentieth-generation descendant of Confucius. My ancestor Confucius and your esteemed ancestor Laozi (Li Er) shared a deep friendship—doesn't that make us family friends across generations?"
Li Yuanli and the other guests were utterly astonished. Li Yuanli graciously invited Kong Rong to take a seat and began a conversation with him.
Soon, Grand Master Chen Wei came to visit Li Yuanli. The guests told him what Kong Rong had just said. Chen Wei disagreed and remarked:
“When young, clever; when grown, not necessarily outstanding.” Kong Rong immediately retorted, “I suppose you must have been very clever when you were young, so...”
The guests were all charmed by Kong Rong's quick wit and burst into laughter, while Chen Wei was left speechless with embarrassment.
Later, the idiom "not very clear" came to describe something vague or not fully understood.
Source: *A New Account of the Tales of the World*, Chapter "Speech and Conversation"
Meaning of the Idiom: Later, the Chinese idiom "不甚了了" came to describe how something vague or not fully understood.