不可

1. Origins, structure, and basic meaning

• Structure: 不可(ふか) expresses a judgment that something is not permitted or not acceptable under a standard.
• Basic usage: It is used when access or use is not allowed and when an evaluation is failing. Typical patterns are 通行不可 and 不可と評価される.

2. Common pitfalls and similar expressions

• Separate the context-specific senses
  • On a notice it can mean “not permitted,” while in an evaluation it can mean “fail” or “unacceptable.”
• Difference from 禁止
  • 禁止(きんし) explicitly prohibits an action, while 不可 marks a decision that something cannot be allowed or accepted under the relevant criteria.