"Omertà" is a term used to describe a code of silence or unspoken rule, especially within organized crime groups. It means keeping quiet and not cooperating with authorities, even when faced with questioning or threats.
Sentences with «omerta»
All the newspaper groups, bar the magnificent exception of the Guardian, maintained a culture of omerta around phone - hacking, even if (like the Telegraph) they had not themselves been involved. (opendemocracy.net)