cooperate vs nullify

cooperate

verb
  • To function in harmony, side by side 

  • To work or act together, especially for a common purpose or benefit. 

  • To allow for mutual unobstructed action 

  • To engage in economic cooperation. 

nullify

verb
  • To prevent from happening. 

  • To make of no use or value; to cancel out. 

  • To make legally invalid. 

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