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:
“Listen to me, as if I were Sybaris barking with all his heads, at the gates of Hell, I will tell you where to take it. But don’t ... don’t open the box!”
—A.I. (Albert Isaac)
“Like other secret lovers, many speak mockingly about popular culture to conceal their passion for it.”
—Mason Cooley (b. 1927)