惊弓之鸟
huai  an shang  zhi

Once Bitten, Twice Shy
This describes a person who is easily frightened because of a traumatic experience.

Geng Lei was a famous archer of the state of Wei. One day while he was on an excursion outside the city with the king of Wei, he saw a bird circling in the sky. He said to the king, “I don’t have to use an arrow. I’ll just pull the bow string and the bird will fall from the sky.”

“Do you have that marvelous skill?” asked the King. Presently they saw the wild goose flying from the east. Geng Ying twanged the string of his bow and indeed the wild goose at once dropped to the ground in front of them. “You’re really a wonderful archer,” said the King with approval. Geng Lei said, “This is a wounded wild goose. From its desolate cry and tired flight, you can see its wound has not yet been healed. When it heard the twang of my bow-string, it thought it was again hit by an arrow, and fell from the sky.” – Anecdotes of the Warring States

Calligraphy by Harrison X. Tu, Confucius Classroom in Denver