nigger vs spook

nigger

noun
  • A person of any kind (particularly as a term of abuse). 

  • A fish, the luderick (Girella tricuspidata). 

  • A friend, particularly a fellow black person, often used as an informal term of address. 

  • A member of any typically dark-skinned people (now especially in combinations like prairie nigger or sand nigger). 

  • A person of black African descent who acts in an unapproved manner (whether positive or negative). 

  • A black person; a person of black African descent. 

verb
  • To perform in blackface. 

  • To behave as a stereotypical black person. 

  • To treat as inferior. 

spook

noun
  • An undercover agent or spy. 

  • A ghost or phantom. 

  • A hobgoblin. 

  • A scare or fright. 

  • A psychiatrist. 

  • A player who engages in hole carding by attempting to glimpse the dealer's hole card when the dealer checks under an ace or a 10 to see if a blackjack is present. 

  • A metaphysical manifestation; an artificial distinction or construct. 

verb
  • To frighten or make nervous (especially by startling). 

  • To become frightened (by something startling). 

  • To haunt. 

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