obviate vs rule out

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). 

adj
  • Synonym of obviative 

noun
  • Synonym of obviative 

rule out

verb
  • To make unavailable. 

  • To reject an option from a list of possibilities. 

  • To disallow. 

  • To make something impossible. 

  • To cross an item out by drawing a straight line through it, as with a ruler. 

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