obstruct vs unstop

obstruct

verb
  • To block or fill (a passage) with obstacles or an obstacle. See synonyms at block. 

  • To get in the way of so as to hide from sight. 

  • To impede, retard, or interfere with; hinder. 

unstop

verb
  • To remove a stoppage; to clear a blockage. 

  • To draw out the stops of (an organ). 

  • To unplug or uncork a container. 

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