An unexpected disaster or misfortune that strikes someone through no fault of their own; an unmerited calamity.

an unexpected disaster or a calamity that strikes out of nowhere; also written as [[无妄之灾|無妄之災|wu2 wang4 zhi1 zai1]] or [[毋妄之祸|毋妄之禍|wu2 wang4 zhi1 huo4]]