let loose vs revel

let loose

verb
  • To shout, make a loud sound, or perform a sudden, vehement action; to behave in a raucous, frenzied manner. 

  • To break wind. 

  • To free; to release from restraint. 

revel

verb
  • To take delight (in something). 

  • To make merry; to have a happy, lively time. 

noun
  • A kind of dance. 

  • An instance of merrymaking; a celebration. 

  • A wake for the dead. 

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