inexpugnable

adj.不能攻占的,不能驳倒的

无法攻克的，无法征服的

形容词

1. The fortress was deemed inexpugnable by the enemy army.
敌军认为这座要塞是无法攻克的。
2. Her determination to succeed was inexpugnable, no matter the obstacles she faced.
无论面临怎样的困难，她都有不可动摇的成功决心。