根拠

1. Origins, structure, and basic meaning

• Structure: 根拠(こんきょ) is a noun for the basis or evidence supporting a claim or judgment.
• Basic usage: It identifies what is supported in 意見の根拠 and marks absence in 根拠のない噂.

2. Common pitfalls and similar expressions

• Claim and support
  • 根拠 is not the opinion itself; it is the reason or evidence that supports believing the opinion.
• Patterns with の
  • 意見の根拠 says what the basis supports, while 根拠のない describes something as unsupported.