wooden rooster
Literal meaning: a rooster carved from wood. Rarely used outside the context of the idiom 木鶏となる or the story from Zhuangzi.
木鶏 refers to the wooden rooster that appears in a parable from Zhuangzi.
unflinching fighting cock; strong individual unaffected by adversity
Figurative use derived from the Zhuangzi story: a person who has reached a state of perfect composure, unmoved by external circumstances. Often used in the phrase 木鶏となる.
He is unshaken by any hardship, truly a person like a wooden rooster.
After years of training, he became an unflinching fighting cock.