abet vs nullify

abet

verb
  • To support, countenance, maintain, uphold, or aid (any good cause, opinion, or action); to maintain. 

  • To incite; to assist or encourage by aid or countenance in crime. 

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 abet and nullify occurred in a corpus of books? (source: Google Ngram Viewer )