unwritten law

noun
1.
a law that rests for its authority on custom, judicial decision, etc., as distinguished from law originating in written command, statute, or decree.
2.
the unwritten law, the supposed principle of the right of the individual to avenge wrongs against personal or family honor, especially in cases involving relations between the sexes: sometimes urged in justification of persons guilty of criminal acts of vengeance.
Origin
1635-45
Examples from the web for unwritten law
  • What they did is the pattern of right, the unwritten law to which he yields a blind unquestioning obedience.
  • Our society needs to believe in an unwritten law that says police deserve our respect and benefit of the doubt.
  • But it would be incorrect to say that common law is unwritten law.
  • Tty an unwritten law the term of four years can be, and often has been, extended to eight years of office.
British Dictionary definitions for unwritten law

unwritten law

noun
1.
the law based upon custom, usage, and judicial decisions, as distinguished from the enactments of a legislature, orders or decrees in writing, etc
2.
the unwritten law, the tradition that a person may avenge any insult to family integrity, as used to justify criminal acts of vengeance
Idioms and Phrases with unwritten law

unwritten law

An accepted although informal rule of behavior, as in It's an unwritten law that you lock the gate when you leave the swimming pool. [ Mid-1400s ]