explore vs feel out

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. 

feel out

verb
  • To try to ascertain a person's point of view, or the nature of a situation, by cautious and subtle means. 

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