omertà

noun2

1. •
   A code of silence amongst members of the Mafia that forbids divulging insider secrets to law enforcement, often also followed outside of the organization for fear of retaliation.

   • Where such a thing as Sicilian omertà exists, the most perfect laws, and the most honestly-intentioned executive in the world cannot escape falling into errors. — 1864
2. •
   (figurative) Any code of silence (especially about something illegal or secret), or refusal to talk openly about something.

   • Over the past ten years, a series of high-profile CEOs have broken unwritten omertas not to address the contentious challenges posed by climate change, human rights, and increased transparency. — 2010