head off vs oppose

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. 

oppose

verb
  • To attempt to stop the progression of; to resist or antagonize by physical means, or by arguments, etc.; to contend against. 

  • To object to. 

  • To place in front of, or over against; to set opposite; to exhibit. 

  • To present or set up in opposition; to pose. 

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