concubine vs harlot

concubine

noun
  • A woman who lives with a man, but who is not a wife. 

  • A slave-girl or woman, kept for instance in a harem, who is held for sexual service. 

  • A sexual partner, especially a woman, to whom one is not or cannot be married. 

harlot

noun
  • A female who is considered promiscuous. 

adj
  • Wanton; lewd; low; base. 

verb
  • To play the harlot; to practice lewdness. 

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