be a law unto oneself—do what one believes is right and ignore established laws or custom:
- If the government becomes a law breaker it invites every man to become a law unto himself.
Note: The expression does not correlate in meaning with the phrase lay down the law—assert smth. positively; state or declare smth. firmly:
- The new basketball coach can recruit, teach and lay down the law, when necessary.
take the law into one’s own hands—get justice in one’s own way, without involving the police:
- These men took the law into their own hands. They killed a score of men who, they said, were outlaws of various kinds.