What is the legal term for failing to act by a public officer to prevent a crime?

The term that accurately describes the failure of a public officer to take appropriate action to prevent a crime is "dereliction of duty." This concept highlights the responsibility of public officials to fulfill their obligations and take action in situations where they have a duty to do so. When a public officer neglects this responsibility, it can result in serious consequences, not only for the officer but also for the public they serve.

Dereliction of duty specifically refers to a breach of duty that can manifest in many forms, such as inaction in the face of a foreseeable crime or failing to enforce laws. It differs from other terms that might imply unethical behavior or negligence in a different context. For example, malfeasance generally refers to wrongdoing or illegal behavior by a public officer, while misconduct could encompass a range of inappropriate actions but does not necessarily imply a failure to act specifically. Negligence typically relates to a private duty of care and isn't specifically used to describe a public officer's responsibilities.