entrench

The story

From en- + trench. First attested in the 1550s.

First known use, by meaning

• from 1590s To become completely absorbed in and fully accept one's beliefs, even in the face of evidence against it and refusing to be reasoned with.
• from 1590s To establish a substantial position in business, politics, etc.
• from 1590s To invade; to encroach; to infringe or trespass; to enter on, and take possession of, that which belongs to another; usually followed by on or upon.