disavow vs swear to

disavow

verb
  • To deny; to show the contrary of; to deny legitimacy or achievement of any kind. 

  • To strongly and solemnly refuse to own or acknowledge; to deny responsibility for, approbation of, and the like. 

swear to

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