cool down vs liberate

cool down

verb
  • To decrease in degree or intensity. 

  • To become cooler; to be reduced in temperature. 

  • To become less agitated or excited. 

  • To cause (something) to become cooler; to reduce the temperature of. 

  • To cause (someone) to become less agitated or excited. 

liberate

verb
  • To release from restraint or inhibition. 

  • To release from chemical bonds or solutions. 

  • To acquire from an enemy during wartime, used especially of cities, regions, and other population centers. 

  • To release from servitude or unjust rule. 

  • To release from slavery: to manumit. 

  • To acquire from another by theft or force: to steal, to rob. 

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