cave in vs disallow

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. 

disallow

verb
  • To refuse to allow 

  • To reject as invalid, untrue, or improper 

  • to overrule a colonial legislation by the sovereign-in-privy council 

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