reposition vs vacillate

reposition

verb
  • To put into a new position 

noun
  • The act of putting into a new position. 

vacillate

verb
  • To swing indecisively from one course of action or opinion to another. 

  • To sway unsteadily from one side to the other; oscillate. 

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