1.
happiness in the afterlife; rest in peace
Blessedness or peace in the world after death. Almost exclusively used in the set expression ご冥福をお祈りします (We pray for your peaceful rest), a standard condolence phrase.
Usage
冥福 is almost always used in the set expression ご冥福をお祈りします, the standard way to express condolences in Japanese. It is appropriate for formal contexts such as funerals, memorial services, and official statements. The word comes from Buddhist terminology.
Some consider this expression inappropriate for non-Buddhist families, since 冥福 is rooted in Buddhist beliefs about the afterlife. In such cases, 哀悼の意を表します (expressing condolences) is a more neutral alternative.