bootlip vs nig-nog

bootlip

noun
  • A black person. 

  • A large lip, especially of a black person. 

  • The lip at the top end of the shaft of a boot. 

nig-nog

noun
  • A person of color, especially, a black person. 

  • A foolish person; hence, a raw and unskilled recruit. 

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