A "Lead Balloon" is a metaphor used to describe an idea, proposal, or joke that fails to gain acceptance or is poorly received. The phrase suggests that, like a lead balloon, which cannot float, the concept is heavy and burdensome, making it ineffective or unwelcome. The origin of the expression is unclear, but it has been in use since the 20th century. It is often employed in discussions about communication, humor, or social interactions, where something intended to be light-hearted or clever falls flat, leading to awkwardness or disappointment.