activate vs fall off

activate

verb
  • To organize or create a military unit or station. 

  • To bring a player back after an injury. 

  • To put a device, mechanism (alarm etc.) or system into action or motion; to trigger, to actuate, to set off, to enable. 

  • To render a substance radioactive. 

  • To hasten a chemical reaction, especially by heating. 

  • To render more reactive; excite. 

  • To remove the limitations of demoware by providing a license; to unlock. 

  • To render a molecule reactive, active, or effective in performing its function. 

  • To encourage development or induce increased activity; to stimulate. 

  • To aerate in order to aid decomposition of organic matter. 

fall off

verb
  • To diminish in size, value, etc. 

  • To fall into sin; stray. 

  • To change the direction of the sail so as to point in a direction that is more down wind; to bring the bow leeward. 

  • To become detached or to drop from. 

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