open up vs puzzle

open up

verb
  • To reveal oneself; to share personal information about oneself; to become communicative. 

  • Synonym of cheat out (“to face or turn toward the audience more than would be natural”) 

  • To begin running, driving, travelling, etc., at maximum speed. 

  • To commence firing weapons. 

  • To rain. 

  • To open. 

  • To widen. 

puzzle

verb
  • To perplex, confuse, or mystify; to cause (someone) to be faced with a mystery, without answers or an explanation. 

  • To think long and carefully, in bewilderment. 

  • To make intricate; to entangle. 

noun
  • Anything that is difficult to understand or make sense of. 

  • A riddle. 

  • The state of being puzzled; perplexity. 

  • A game for one or more people that is more or less difficult to work out or complete. 

  • A jigsaw puzzle. 

  • A crossword puzzle. 

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