invulnerable

这种新材料几乎坚不可摧，能抵御任何冲击。

This new material is nearly ___invulnerable to any impact.

经历了那么多挫折后，他已经变得刀枪不入，任何负面评价都影响不到他了。

After so many setbacks, he has become ___invulnerable to any negative comments.