wall of silence vs blue wall of silence

wall of silence and blue wall of silence both are nouns.

Word	Noun	Adjective	Verb	Adverb
wall of silence	Yes	No	No	No
blue wall of silence	Yes	No	No	No

As nouns, wall of silence and blue wall of silence are synonyms defined as:

wall of silence and blue wall of silence: the secrecy of police officers who lie or look the other way to protect other police officers

Other synonyms of wall of silence include blue wall.

wall of silence (noun)	blue wall of silence (noun)
the secrecy of police officers who lie or look the other way to protect other police officers	the secrecy of police officers who lie or look the other way to protect other police officers