cave in vs overcome

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. 

overcome

verb
  • To surmount (a physical or abstract obstacle); to prevail over, to get the better of. 

  • To prevail. 

  • To win or prevail in some sort of battle, contest, etc. 

  • To recover from (a difficulty), to get over 

  • To come or pass over; to spread over. 

noun
  • The burden or recurring theme in a song. 

  • A surplus. 

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