cave in vs forge

cave in

noun
  • The act of something collapsing or caving in. 

  • The act of relenting. 

  • The location where something has caved in. 

verb
  • To collapse inward or downward. 

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

forge

noun
  • The act of beating or working iron or steel. 

  • A Web-based collaborative platform for developing and sharing software. 

  • A furnace or hearth where metals are heated prior to hammering them into shape. 

  • A workshop in which metals are shaped by heating and hammering them. 

verb
  • To make falsely; to produce, as that which is untrue or not genuine; to fabricate. 

  • To move forward heavily and slowly (originally as a ship); to advance gradually but steadily; to proceed towards a goal in the face of resistance or difficulty. 

  • To create a forgery of; to make a counterfeit item of; to copy or imitate unlawfully. 

  • To advance, move or act with an abrupt increase in speed or energy. 

  • To form or create with concerted effort. 

  • To shape a metal by heating and hammering. 

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