deceased person; the dead; casualties
Formal term used in official contexts, reports, or news for people who have died, especially in accidents or disasters. Often interchangeable with 死者, but 死没者 can sound more bureaucratic.
See also: 死者
The number of casualties in the accident was announced as three.
The list of the deceased was made public.
死亡者 also means 'deceased person' or 'fatality', but is slightly more common than 死没者. 死没者 can imply a more respectful or bureaucratic tone.
Compound of 死没 (death, passing away) and 者 (person). The term is a straightforward Sino-Japanese formation.