let out vs secrete

let out

verb
  • To disclose. 

  • Of a school: to finish for the day or term, allowing the pupils to go home. 

  • To rent out. 

  • Of sound, to emit. 

  • To allow to operate at higher speed by adjusting controls. 

  • To release. 

  • To enlarge by adjusting one or more seams. 

secrete

verb
  • To conceal. 

  • To extract a substance from blood, sap, or similar to produce and emit waste for excretion or for the fulfilling of a physiological function. 

  • To exude or yield. 

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