“homicide by misadventure." . . . is when somebody accidentally
kills somebody else while engaged in a legal activity and without any
intent to cause harm.
There is a criminal offense sometimes called negligent homicide, and sometimes called involuntary manslaughter (in some jurisdictions this is limited to, for example, vehicular homicide and homicide caused with a deadly weapon or involving a child or vulnerable adult).
Where this offense is present, it requires a level of intent of at least "criminal negligence" which is roughly equivalent to "gross negligence" in civil lawsuits and is almost, but not quite recklessness.
But if the conduct causing the death involves merely ordinary negligence at a level providing a basis for a civil action for negligence, or only involves acts which unforeseeably cause death despite the fact that the person carrying out the act used the care of a reasonable person under the circumstances (in which case there is a basis for a civil lawsuit only in the rare circumstances where there is strict liability), this is not a crime.
Sometimes, however, the conduct involved may violate some other law (e.g. speeding or hunting after having already reached one's game kill limit) that is a lesser crime, even though it is not a homicide crime.