impersonate vs unmask

impersonate

verb
  • To pretend to be (a different person); to assume the identity of. 

  • To operate with the permissions of a different user account. 

unmask

verb
  • To expose, or reveal the true character of someone. 

  • To cease engaging in masking, to cease disguising one's autism. 

  • To enable (an interrupt, etc.) by unsetting or setting the associated bit. 

  • To remove a mask from someone. 

  • To remove one's mask. 

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