noun
adult ward
Legal term for an adult placed under guardianship (成年後見制度) due to diminished mental capacity; the guardian (成年後見人) manages their affairs.
成年被後見人は、法律行為を単独で行うことが制限される場合がある。
An adult ward may be restricted from performing legal acts independently.
Compound of 成年 (adult) + 被後見人 (person under guardianship). The term is a modern legal coinage under Japan's adult guardianship system.