misadventure        
noun [ C ]  literary uk/ˌmɪs.ədˈven.tʃər/ us/ˌmɪs.ədˈven.tʃɚ/
 不幸事故;不幸遭遇;厄运
an accident or bad luck
 death by misadventure law UK specialized 意外致死,意外死亡
the official expression used in court for a death that happens by accident
  The coroner recorded a verdict of death by misadventure. 验尸官所作出的鉴定结论是意外致死。 
 The official verdict was death by misadventure.
 At the inquest, the verdict was death by misadventure.
 A verdict of death by misadventure was returned on the 52-year-old teacher from Devon.
 The coroner recorded a verdict of death by misadventure and extended her sympathies to the family.