What if I am asked a question, and respond with an untruth I know is untrue, and I don't really care if I am believed, but definitely don't want to be found out (I don't want anyone to know Ive uttered an untruth). Is that a lie, if I am fairly sure I will be believed?
Words are tricky things, so let's analyze after using a defintion: A lie is a communication with the intent to deceive. We can now ask if your words qualify.
What if I am asked a question, and respond with an untruth I know is untrue, and I don't really care if I am believed, but definitely don't want to be found out (I don't want anyone to know Ive uttered an untruth)
Notice with our definition, you have communicated, so that part of the definition is fulfilled. The question now arises as to whether you have done so with an intent to deceive?
You have perpetuated a falsity. You know you have perpetuated a falsity. You have moral qualms you have perpetuated a falsity. You know that you can be and might be found out having perpetuated a falsity. And, you don't want to be perceived as having perpetuated that falsity.
That seems rather iron-clad a set of conditions to characterize as deception. A person who perpetrates falsities without regard for their truthfulness is a BSer, but one who knows they're passing on falsehoods and seeks to conceal it is a liar.
This is what Harry Frankfurt was discussing in On Bullshit. The BS'er doesn't care if what they say is true or not. For that, they might not care whether what they say is accepted by their audience; they might be recklessly inciting acceptance of whatever beliefs, but this is like the distinction between murder and manslaughter, say (or at least between different degrees of either), but in their own eyes, "It's not like I expect them to listen to me!"
The negative consequences they might fear are not of being found out for dishonesty in the normal sense: they might wish to merely not be thought of as a BS'er, here, or not thought of as being liars for being BS'ers instead. They might take the subtle formal difference between lying and BS as more important than it might sound to others, like a psychological torturer exclaiming, "Well, at least I don't really hurt them, not like those other fellows!" i.e. the ones with knives and lighters and so on. But so while there is arguably a technical, quibbling-theoretic reason to distinguish a liar's fear-of-consequences from a BS'ers, there might not be much, if ever any, ethical distance between the two types of acts.