skivvy vs slave-girl

skivvy

noun
  • A prostitute. 

  • A close-fitting, long-sleeved T-shirt with a rolled collar. 

verb
  • To perform menial work; to do chores, like a servant. 

slave-girl

noun
  • A female required to perform sexual acts, a sex slave. 

  • A female slave. 

How often have the words skivvy and slave-girl occurred in a corpus of books? (source: Google Ngram Viewer )