enchain vs loosen

enchain

verb
  • To restrain with, or as if with, chains. 

  • To link together. 

loosen

verb
  • To disengage (a device that restrains). 

  • To make loose. 

  • To free from restraint; to set at liberty. 

  • To become unfastened or undone. 

  • To relieve (the bowels) from constipation; to promote defecation. 

  • To become loose. 

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