conceal vs unfurl

conceal

verb
  • To hide something from view or from public knowledge, to try to keep something secret. 

unfurl

verb
  • To open up by unrolling. 

  • To roll out or debut anything. 

  • To turn out or unfold; to evolve; to progress. 

  • To unroll or release something that had been rolled up, typically a sail or a flag. 

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