未成年

1. Origins, structure, and basic meaning

• Structure: 未成年 (みせいねん) is a noun for a minor or the state of being underage.
• Basic usage: It identifies a character as still a minor or marks underage participants as requiring guardian consent.
  • 物語の主人公はまだ未成年である。 — The story's protagonist is still a minor.
  • 未成年の参加者には保護者の同意を求めた。 — Underage participants needed a guardian's consent.

2. Common pitfalls and similar expressions

• Person and status
  • 未成年 can identify a person or their underage status; with another noun, it appears as 未成年の参加者.