An adverse event, calamity, or evil fortune, arising by accident, (or without the will or concurrence of him who suffers from it,) and not to be foreseen or guarded against by care or prudence. See 20 Q. B. Div. 810. In its application to the law of homicide, this term always involves the further idea that the person causing the death is not at the time engaged in any unlawful act. 4 Bl. Comm. 182.