instigate vs obviate

instigate

verb
  • to incite; to bring about by urging or encouraging 

  • to goad or urge (a person) forward, especially to wicked actions; to provoke 

obviate

noun
  • Synonym of obviative 

adj
  • Synonym of obviative 

verb
  • To avoid (a future problem or difficult situation). 

  • To anticipate and prevent or bypass (something which would otherwise have been necessary or required). 

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