head off vs obviate

head off

verb
  • To avoid the undesirable consequences of; prevent. 

  • To start out. 

  • To intercept. 

  • To turn away from the wind. 

  • To begin moving away. 

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 head off and obviate occurred in a corpus of books? (source: Google Ngram Viewer )