air out vs freshen

air out

verb
  • To expose to air; to leave open or spread out, as to allow odor or moisture to dissipate. 

  • To throw passes, especially long and high passes. 

  • To discuss in the open; to address an issue or conflict that has long been avoided. 

freshen

verb
  • To remove or cover unpleasant qualities such as staleness, bad odour or taste (in air, breath, water, etc.). 

  • To top up (a drink). 

  • To touch up (makeup); to give (a body part, especially the face) a quick wash. 

  • To make less salty; to separate, as water, from saline ingredients. 

  • To make cool. 

  • To be refreshed. 

  • To touch up the paint on (something). 

  • To become not salty, to lose its salinity. 

  • To become cool. 

  • To refresh; to revive; to renew. 

  • To make green (vegetation that has become dry). 

  • To top up (primer) in a firearm. 

  • To give redness to (the face or cheeks of a person with light skin). 

  • To begin or resume giving milk, especially after calving; to cause to resume giving milk. 

  • To relieve, as a rope, by change of place where friction wears it; or to renew, as the material used to prevent chafing. 

  • To become stronger. 

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