incog vs such-and-such

incog

noun

  • Incognito. 

adv

  • Incognito. 

adj

  • Incognito. 

such-and-such

noun

  • A placeholder or generic thing. 

det

  • indefinite; some or other, not stated 

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