accede vs cave in

accede

verb
  • To agree or assent to a proposal or a view; to give way. 

  • To become a party to an agreement or a treaty. 

  • To come to an office, state or dignity; to attain, assume (a position). 

cave in

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

  • To collapse inward or downward. 

noun
  • The act of relenting. 

  • The location where something has caved in. 

  • The act of something collapsing or caving in. 

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