cave in vs give in

cave in

verb
  • To collapse inward or downward. 

  • To relent; to grant approval against one's initial will. 

noun
  • The act of relenting. 

  • The location where something has caved in. 

  • The act of something collapsing or caving in. 

give in

verb
  • to collapse or fall 

  • to droop the head 

  • to relent, yield, surrender or admit defeat 

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