真剣

1. Origins, structure, and basic meaning

• Structure: Written 真剣 and read しんけん, it means serious and fully attentive, and also denotes a real sharpened sword.
• Basic usage: It appears in athletes' intent expressions and in a warning not to touch a sword on display.

2. Common pitfalls and similar expressions

• Serious attitude versus real blade
  • Context must distinguish the adjectival sense from the noun naming a genuine sword.