無頓着

1. Origins, structure, and basic meaning

• Structure: The adjectival noun 無頓着 (むとんちゃく) describes being unconcerned or indifferent about something.
• Basic usage: The matter takes に in 服装に無頓着だ, while apparent indifference can be 無頓着なふり.

2. Common pitfalls and similar expressions

• Indifference to a matter
  • It is not the same as ignorance; one may know about something yet attach little importance to it.