the walls have ears

The phrase "the walls have ears" is an expression used to convey the idea that one should be cautious about speaking freely or sharing private information because it is possible for someone else to listen or eavesdrop. It suggests that even in apparently private spaces, there might be hidden or unknown individuals who can overhear conversations or gather information. It serves as a reminder to be mindful of one's surroundings and the potential for unintended listeners.