Wall Of Silence Meaning

(idiomatic) Strict secretiveness maintained by the members of a group with respect to information which might be contrary to their interests, especially information concerning questionable actions by members of the group.

Example: 1981 Aug 6, “Rebel with a Cause: The real-life story of an anti-Mafia activist in Sicily makes for a handsome film with a political message,” Time:
  That makes his struggle with the culture of omertà, the wall of silence that allowed the Mafia to prevail for decades, all the more poignant.
1994 May 15, James Sterngold, "Japanese Begin to Crack the Wall Of Secrecy Around Official Acts," New York Times (retrieved 10 Aug 2012):
  Her parents sought the official report on the incident, but they have run into a wall of silence.
2010 March 9, Melissa Eddy and Alessandra Rizzo, "Pope's brother: I ignored physical abuse reports," Businessweek (retrieved 11 Aug 2012):
  German justice minister, Sabine Leutheusser-Schnarrenberger, said Monday that a Vatican secrecy rule has played a role in a "wall of silence" surrounding sexual abuse of children.