What is "wall of silence"

n. (context idiomatic English) 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.

n. the secrecy of police officers who lie or look the other way to protect other police officers; "the blue wall cracked when some officers refused to take part in the cover-up" [syn: blue wall of silence, blue wall]