The phrase "most sub rosa" refers to something that is secret or confidential. Antonyms for this phrase could include terms like open, public, or exposed. If something is open or public, it is not hidden or concealed in any way. These terms suggest a sense of transparency or honesty, rather than hidden motives or secret behavior. Similarly, if something is exposed, it is no longer hidden or secret, but rather has been revealed or brought to light. Antonyms for "most sub rosa" thus suggest the opposite of secrecy and concealment, offering a more direct, upfront approach to communication, decision-making, and behavior.