entrench

Etymology

Mid-16th century. en- + trench

verb

1. (construction, archaeology) To dig or excavate a trench; to trench.
2. (military) To surround or provide with a trench, especially for defense; to dig in.
   The army entrenched its camp, or entrenched itself.
3. (figurative) To establish a substantial position in business, politics, etc.
   Senator Cornpone was able to entrench by spending millions on each campaign.
   Given these entrenched ideological assumptions about the colonial order, it is no wonder that the state and those groups with an interest in the status quo viewed with suspicion and hostility any challenges to the fixed and "natural" boundaries between different sorts of people. 2009, Andrew B. Fisher, Matthew O'Hara, “Forward”, in Andrew B. Fisher, Matthew O'Hara, editors, Imperial Subjects: Race and Identity in Colonial Latin America, page 4
   For London to have its own exclusive immigration policy would exacerbate the sense that immigration benefits only certain groups and disadvantages the rest. It would entrench the gap between London and the rest of the nation. And it would widen the breach between the public and the elite that has helped fuel anti-immigrant hostility. September 28 2013, Kenan Malik, “London Is Special, but Not That Special”, in New York Times, retrieved 2013-09-28
4. 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.
5. To cut in; to furrow; to make trenches in or upon.
6. (figurative) 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.