I don't think people use "bullshitting" interchangably with "lying". I'm partial to this characterization:

So bullshitting isn’t just nonsense. It’s constructed in order to appear meaningful, though on closer examination, it isn’t. And bullshit isn’t the same as lying. A liar knows the truth but makes statements deliberately intended to sell people on falsehoods. bullshitters, in contrast, aren’t concerned about what’s true or not, so much as they’re trying to appear as if they know what they’re talking about. ... [W]hen people speak from a position of disproportionate confidence about their knowledge relative to what little they actually know, bullshit is often the result. [1]

Doesn't this description like what LLMs do all the time?

[1] https://www.psychologytoday.com/us/blog/psych-unseen/202007/...