unfit for military duty (historical); person unfit for conscription
Historical term from the former Japanese military conscription system. Refers to a classification (丁種) given to individuals who failed the physical examination and were deemed unfit for service. The term can also refer to the person so classified. Not used in modern military contexts.
In prewar Japan, those who failed the conscription physical were classified as teishu (unfit for duty).
Because he was frail, he was exempted from military service as a teishu.