misadventure
A fatal mishap, especially one voluntarily risked by the victim, bad luck causing an accidental death without attaching any liability to any other involved parties.
uncountable
There were, however, 34 deaths among passengers in movement accidents, due mainly to misadventure and carelessness when entering and leaving trains in motion, falling off platforms and out of carriages, and opening and closing carriage doors.
Where it comes from
From Middle English misaventure, from Old French mesaventure, from mes- (“mis-”) + aventure (“adventure”). Equivalent to mis- + adventure. Compare disadventure.
Adapted from the Wiktionary entry misadventure (CC BY-SA 4.0).