impede vs obviate

impede

verb
  • To get in the way of; to hinder. 

obviate

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

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

noun
  • Synonym of obviative 

adj
  • Synonym of obviative 

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