(as) stubborn as a mule
01
頑固すぎる, 自分の考えを曲げない
used to describe someone who refuses to change their opinion or chosen course of action
例
Despite the advice from experts, he insisted on doing things his own way, proving to be stubborn as mules in accepting any guidance.
兄は頑固すぎて、自分が間違っていると認めない。
