entrench, intrench – (verb) to fix, from the literal meaning: to dig a trench around a position (in the army) – see picture

entrenched, intrenched – (verb) fixed

 Reinis Traidas

Examples:

The rich have entrenched themselves in all branches of the government.

He had entrenched himself in the wrong ideas, and it was very hard for him to see the truth.

She used to be open-minded but lately she’s become entrenched in the past.

Religious views are still deeply entrenched in our society.

It will be hard to eradicate (= get rid of) entrenched corruption in our office.