沈着

1. Origins, structure, and basic meaning

• Structure: 沈着 is read as ちんちゃく and can be a na-adjective for composure or a noun and する verb for material settling and becoming deposited.
• Basic usage: Calm judgment appears in 沈着な判断, while a substance settling on a surface appears in 物質が沈着する.

2. Common pitfalls and similar expressions

• Human composure and material deposition
  • Context distinguishes an unshaken manner in an emergency from material settling out of a liquid and collecting on a surface.
• Difference from 冷静
  • 冷静 broadly means calm and not carried away by emotion, while human 沈着 emphasizes steady judgment and conduct even in a crisis.