Inspired by Harry G Frankfurt's essay On Bullshit, bullshit is a term I use to describe babble that is neither true nor false. In software engineer, project estimates are a common form of bullshit. Think of this way:
facts: truthiness == true lies: truthiness == false bullshit: truthiness == null
bullshit is something that can be "Not Even Wrong", because it fails to meet the criteria where correctness or incorrectness can be determined. To put it another way, bullshit is "not even true."
Brandolini's Law - "The amount of energy needed to refute bullshit is an order of magnitude larger than to produce it."
When people are talking bullshit, it doesn't matter if what they are saying is true or not. The goal of the bullshit is to convey an impression of oneself.
You can't lie unless you think you know the true. Bullshit has no such pre-requisite.