Antonyms for the phrase "blows the lid off" include conceals, hides, covers up, suppresses, and withholds information. These antonyms suggest the act of keeping a secret or maintaining privacy over a matter. When someone "blows the lid off" something, they are exposing the truth or bringing to light something that was previously hidden. In contrast, the antonyms indicate an intentional effort to keep something out of the public eye. These words highlight the importance of discretion and confidentiality, especially in professional and personal relationships where sensitive information may be at stake.