expunge vs unsnib

expunge

verb
  • To erase or strike out. 

  • To eliminate completely; to annihilate. 

  • To delete permanently (e-mail etc.) that was previously marked for deletion but still stored. 

unsnib

verb
  • to undo, untie, or open or become undone, untied, or opened. 

  • Somehow she managed to unsnib the window and escape. 

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