During the Jin Dynasty, there lived a very handsome and talented general named Wang Ji who was very well-known in the city. One year, his nephew Wei Jie and his mother came to seek refuge with him. Wang Ji was impressed by Wei Jie's grace and fine features.
A few days later, Wang Ji took Wei Jie to visit friends and relatives. Wei Jie caused a sensation as passersby clamored to take a closer look as he walked down the street. When they arrived at a relative's house, they wanted to know whether Wei Jie's knowledge was as exceptional as his appearance. So they insisted he lecture on metaphysics. Wei Jie had no choice but to comply and although he only spoke for a short while, those who heard his ideas unanimously praised his clarity.
People laughed merrily, "it appears no-one compares to Wei Jie!" Wang Ji said, "Yes. Walking with my nephew is like walking beside a bright pearl. I am reduced to the shadows".
The original meaning of "自惭形秽" is to feel ashamed because one is not as good looking as another. Later the meaning evolved to mean one being ashamed for not being as talented or accomplished as another.
例句:
1、听他滔滔不绝地说起专业知识,我就自惭形秽了。 Listening to his expertise, I was ashamed by my ignorance.
2、跟您所做的工作比起来,我真是自惭形秽。 In comparison with your work, mine leaves me ashamed.