undo vs unloose

undo

verb
  • To unfasten. 

  • To reverse the effects of an action. 

  • To impoverish or ruin, as in reputation; to cause the downfall of. 

noun
  • An operation that reverses a previous action. 

unloose

verb
  • To become loose or come off. 

  • To loosen or undo (something that entangles, fastens, holds, or interlocks). 

  • To free (someone or something) from a constraint; (figuratively) to release (something which has been suppressed, such as emotions or objectionable things). 

  • To relax or slacken (something that clasps or grips, such as the arms or hands). 

  • To free from a constraint. 

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