According to Rules

used to say that one is free from suspicion or danger of wrongdoing

She is in the clear now that all the obstacles have been overcome.

used to refer to a situation in which one is taking legal action to solve a problem or crime

Officers on the case are unable to find a motive.

used to refer to the ability of the legal system and police to enforce justice and punish criminals

The arm of the law enforces justice and upholds the rule of law.

a tough and forceful way of questioning someone in order to make them reveal information or admit to something, often using harsh methods

The suspect is being subjected to the third degree in the interrogation room.

used to refer to someone who is imprisoned or serving time in prison

The notorious criminal is currently behind bars, serving a life sentence for his crimes.

to be expecting something difficult or undesirable to happen

When they heard the thunder, they knew they were in for a stormy evening.

strictly adhering to established rules, procedures, or standardized practices

The detective solved the case by the book, meticulously gathering evidence and following every procedure.

rules that determine what one should or should not do in a particular situation

The employee should follow the dos and don'ts outlined in the company handbook.

approval to begin a project

The manager gives the green light for the project to proceed.

a method or principle solely based on experience, which may not be completely accurate

The rule of thumb suggests that you should save at least 10% of your income.

used to admit that the accusations or charges against one are true

Did you forget to send that email I asked you about?

a doctor's report stating that the patient is in good physical or mental health

He's been given a clean bill of health by the doctor.