unbreakable

1. ADJ Unbreakable objects cannot be broken, usually because they are made of a very strong material. 不会被打破的

Tableware for outdoor use should ideally be unbreakable. 户外使用的餐具最好是不容易被打破的。

2. ADJ An unbreakable rule or limit must be obeyed. 必须遵守的

One unbreakable rule in our school is that no child can be tested without written parental permission. 我们学校必须遵守的规定是：没有家长的书面允许不能给孩子做测试。