Entrenched ideas are so fixed or have existed for so long that they cannot be changed.

It's very difficult to change attitudes that have become so deeply entrenched over the years. 改变多年以来形成的根深蒂固的旧看法是很困难的。

The organization was often criticized for being too entrenched in its views. 这个组织死守着自己的观点不变，因此常常受到批评。