Definition - What does Misadventure mean?
A misadventure is when a person dies purely as the result of an accident without anyone performing an unlawful act to cause the death. In this way, a misadventure is different from involuntary manslaughter and voluntary manslaughter, where deaths arise as the result of unlawful acts or various types of negligence committed.
Justipedia explains Misadventure
Because misadventures do not involve any unlawful acts, no one is prosecuted for them. For example, if a man is hiking on a trail, and a boulder falls on him and kills him, this would be a misadventure. No one did anything unlawful to make the death come about. It simply happened as the result of an accident. If someone had pushed the boulder onto the man, however, that would be a different case.