encroach vs entrench

encroach

verb
  • to intrude unrightfully on someone else’s rights or territory 

  • to advance gradually beyond due limits 

noun
  • Encroachment. 

entrench

verb
  • 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. 

  • To surround or provide with a trench, especially for defense; to dig in. 

  • To establish a substantial position in business, politics, etc. 

  • To dig or excavate a trench; to trench. 

  • To cut in; to furrow; to make trenches in or upon. 

  • 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. 

How often have the words encroach and entrench occurred in a corpus of books? (source: Google Ngram Viewer )