attest vs disavow

attest

verb
  • To affirm to be correct, true, or genuine. 

  • To certify in an official capacity. 

  • To put under oath. 

  • To supply or be evidence of. 

  • To certify by signature or oath. 

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. 

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