nig-nog vs wench

nig-nog

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

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

wench

noun
  • A black woman (of any age), especially if in a condition of servitude. 

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