Unlike the practice (dare I say "tradition") on the Forum, I used the word lie to describe the content, not the motivation. Lying, as defined by St. Thomas Aquinas, is a statement at variance with the mind. That definition applies equally to the teller and the audience. A lie, whether representing something that is false as true or something that is true as false, is simply a falsehood. It is not necessary that one has to know something to be false for it to be a lie.
Well, wouldn’t one have to know or, at least, to be culpably (vincibly) ignorant of the truth to have sinned when speaking a falsehood?