重大

1. Origins, structure, and basic meaning

• Structure: 重大 (じゅうだい) is a na-adjective for something highly important or serious in its impact or consequences.
• Basic usage: 重大な事故 modifies a serious accident, while 重大に受け止める means to treat a situation as grave.
  • 小さな見落としが重大な事故につながることもある。 — A small oversight can lead to a serious accident.
  • 委員会は事態を重大に受け止めた。 — The committee treated the situation as grave.

2. Common pitfalls and similar expressions

• Size and seriousness
  • 大きい broadly describes physical size or degree, whereas 重大 evaluates the weight of consequences, responsibility, or a situation.