loosen vs rivet

loosen

verb
  • To become unfastened or undone. 

  • To make loose. 

  • To free from restraint; to set at liberty. 

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

  • To become loose. 

  • To disengage (a device that restrains). 

rivet

verb
  • To make firm or immovable. 

  • To command the attention of. 

  • To attach or fasten parts by using rivets. 

  • To install rivets. 

noun
  • Any fixed point or certain basis. 

  • A cylindrical mechanical fastener that attaches multiple parts together by fitting through a hole and deforming the head(s) at either end. 

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