incognito vs last name

incognito

noun
  • One unknown or in disguise, or under an assumed character or name. 

  • The assumption of disguise or of a feigned character; the state of being in disguise or not recognized. 

adv
  • Without revealing one's identity. 

adj
  • Without being known; in an assumed character, or under an assumed title; in disguise. 

last name

noun
  • One's family name; surname. 

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