man-killer vs manslaughter

man-killer

noun
  • A murderer. 

  • An animal that kills humans. 

  • Someone who habitually seduces men. 

manslaughter

noun
  • The unlawful killing of a human, either in negligence or incidentally to the commission of some unlawful act, but without specific malice, or upon a sudden excitement of anger; considered less culpable than murder, but more culpable than justifiable homicide. 

How often have the words man-killer and manslaughter occurred in a corpus of books? (source: Google Ngram Viewer )