den vs lurk

den

noun
  • A squalid or wretched place; a haunt. 

  • Synonym of fort (“structure improvised from furniture, etc. for playing games.”) 

  • A comfortable room not used for formal entertaining. 

  • A group of Cub Scouts of the same age who work on projects together. 

  • A small cavern or hollow place in the side of a hill, or among rocks; especially, a cave used by a wild animal for shelter or concealment. 

verb
  • To ensconce or hide oneself in (or as in) a den. 

lurk

noun
  • The act of lurking. 

verb
  • To hang out or wait around a location, preferably without drawing attention to oneself. 

  • To read an Internet forum without posting comments or making one's presence apparent. 

  • To saddle (a person) with an undesirable task or duty. 

  • To remain unobserved. 

  • To remain concealed in order to ambush. 

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