secret of Polichinelle

plural secrets of Polichinelle

1. A supposed secret known to everyone.

   British public life specializes in an elegant variation of the secret of Polichinelle. After a secret is disclosed it may still be treated as if it were a secret.

   1992, Hyman Gross, Ross Harrison, Jurisprudence: Cambridge Essays

   2 more examples

   In October and November 1910 there was a great secret of Polichinelle. Conceivably we may learn from some future historian even more about it than we knew at the time.

   1915, Frederick Scott Oliver, Ordeal by Battle

   It is said that Polst fell because he revealed in an unlucky interview the Secret of Polichinelle, the secret which all the world knew, the secret that there was a claque at the Metropolitan Opera House.

   1926, W. J. Thorold, Arthur Hornblow, Perriton Maxwell, Stewart Beach, editors, Theatre magazine, volumes 43-44

   Synonyms: open secret