act as a witness vs disavow

act as a witness

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 act as a witness and disavow occurred in a corpus of books? (source: Google Ngram Viewer )