entrench

Meanings

1. To cut in; to furrow; to make trenches in or upon.
2. To dig or excavate a trench; to trench.
3. To surround or provide with a trench, especially for defense; to dig in.
4. 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.
5. To establish a substantial position in business, politics, etc.
6. 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.

Etymology

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