This is the 4204th most frequent Chinese word.
坚不可摧
Unbreakable and indestructible.
Here, '坚不可摧' emphasizes the enduring and strong nature of the friendship.
他们之间的友谊坚不可摧，时间和距离都无法影响。
Their friendship is indestructible; time and distance cannot affect it.
The phrase '坚不可摧' describes the unwavering strength of his will.
他的意志坚不可摧，无论遇到什么困难都能坚持到底。
His will is indestructible; he can persevere no matter what difficulties he encounters.
In this sentence, '坚不可摧' illustrates the strong and durable construction of the castle.