hinder vs unstop

hinder

verb
  • To delay or impede; to keep back, to prevent. 

  • To make difficult to accomplish; to act as an obstacle; to frustrate. 

noun
  • The buttocks. 

adj
  • Of or belonging to that part or end which is in the rear or hind, or which follows. 

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 hinder and unstop occurred in a corpus of books? (source: Google Ngram Viewer )