The phrase "blew the lid off" refers to revealing something hidden or secret. Antonyms for this phrase may include concealing, hiding, covering up, or masking. In other words, if something is "blown off the lid", it becomes public knowledge or is widely exposed. Conversely, if it remains concealed, it remains hidden from view, and its existence or details may be unknown or unclear. Antonyms for "blew the lid off" could be used in situations where one wishes to keep information private or confidential, or where there is a desire for secrecy or discretion.