minority; underage
Rare, archaic term for being under the legal age of adulthood. In modern Japanese, 未成年 is the standard word.
In old legal documents, the expression 未丁年 can sometimes be seen.
The exact derivation is uncertain; the kanji 未 (not yet) and 丁年 (adult age) combine to mean 'not yet adult age'. 丁年 itself is an old term for adulthood.