explore vs undersee

explore

verb
  • To examine or investigate something systematically. 

  • To travel somewhere in search of discovery. 

  • To be engaged exploring in any of the above senses. 

  • To examine diagnostically. 

  • To (seek) experience first hand. 

  • To seek sexual variety, to sow one's wild oats. 

  • To wander without any particular aim or purpose. 

noun
  • An exploration; a tour of a place to see what it is like. 

undersee

verb
  • To look intently into; examine; inspect. 

  • To see or look under or below; see below the surface of. 

  • To neglect; fail to see properly or adequately; turn a blind eye to; ignore. 

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