open secret

plural open secrets

1. Information that is widely known, but not acknowledged openly.

   At that time, the corruption in the mayor's office was an open secret.

   4 more examples

   1894, Alvan S. Southworth, "A Generation of the New York Bar", in Frank Leslie's Popular Monthly (later The American Magazine), Volume XXXVII, page 427, It was an open secret in the profession at that time that Mr. Field had very explicit documentary evidence that would have made Mr. Evarts very uncomfortable had the Bar Association thrown down the gauntlet.

   Speed limits apply at many points on the line, in addition to the general 25 m.p.h. limit over the whole Dromod-Belturbet section, but it is an open secret that speeds often rise above the statutory limit.

   1951 May, R. K. Kirkland, “The Cavan & Leitrim Railway”, in Railway Magazine, pages 343-344

   It is now an open secret that Gulf states have developed ties with Israel, in the absence of formal relations, including trade partnerships and security deals.

   2018 November 3, Hassan Hassan, “The Arab Winter Is Coming”, in The Atlantic

   The relationship between [Laurent] Freixe and his subordinate was an “open secret” in the company's management, current and former Nestlé executives tell the FT.

   2025 September 20, Madeleine Speed, Mercedes Ruehl, “The meltdown at Nestlé”, in FT Weekend, London: The Financial Times Ltd., →ISSN, →OCLC, page 6

   Synonyms: secret of Polichinelle

2. datedInformation that is not widely known, despite being freely available.

   The wonderful dining options in this city are hidden gems — an open secret.