The antonyms for "brought out into the open" could include "concealed," "hidden," "buried," "obscured," "veiled," or "suppressed." These terms suggest a lack of openness or transparency, a preference for secrecy or privacy, or a desire to keep something hidden from view. In contrast to "brought out into the open," which implies a willingness to acknowledge or confront an issue or problem, these antonyms suggest a reluctance to do so, or even an active effort to keep things hidden or covered up. When seeking to express the opposite of "brought out into the open," these words can provide useful alternatives for conveying different shades of meaning and nuance.