Sambo vs nig-nog

Sambo

noun
  • A black person, especially one who is accommodating or servile towards whites; an Uncle Tom. 

name
  • A nickname from the given name Samantha. 

  • A Russian martial art and combat sport. 

  • A nickname from the given name Samuel. 

nig-nog

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

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

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