断る

1. Origins, structure, and basic meaning

• Structure: 断る (ことわる) can mean refusing a request or notifying someone beforehand to obtain acknowledgment.
• Basic usage: A person politely declines an invitation; before taking a photograph, they first say something to the other party.

2. Common pitfalls and similar expressions

• Rejecting an invitation and giving advance notice
  • 誘いを断った is refusal, while 一言断る is prior notice or acknowledgment. The latter does not mean refusing to take the photograph.