manslaughter UK /ˈmænˌslɔːtə/US /ˈmænˌslɔtɚ/ noun2 •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. •(no longer used) The slaying of a human being. formsmanslaughters