An open secret is a concept or idea that is "officially" secret or restricted in knowledge, but is actually widely known; or refers to something which is widely known to be true, but which none of the people most intimately concerned are willing to categorically acknowledge in public.
Famous quotes containing the words open and/or secret:
“What is not in the open street is false, derived, that is to say, literature.”
—Henry Miller (1891–1980)
“Then is it sin
To rush into the secret house of death
Ere death dare come to us?”
—William Shakespeare (1564–1616)