so... "mendacious" is not the same kind of word as "lie". "Mendacio" is "lie" in Latin (and Spanish and possibly some other Latin languages). "lie" as people actually use the term in English is a base term, like "mendacio" in Latin or Spanish. You can change it's harshness with context. That said, it is true that some people are offended with the use of the word "lie" in some contexts (but not others). None of this matters much to me. What matters is that the word concept for "lie" is a core cognitive one that people readily understand and use frequently. It is a stable and linguistically universal word concept. Not so many people understand "mendacious" because of its additional complexities of reference. It's not a very stable word concept and may (or may not) disappear. If you take a three year old he will grin if you say something he said is a lie. He will just stare if you say to him that he is being mendacious. (P.S. this is a context where "lie" is not such a harsh term). I can make any term a harsh term with context...witness the recent harshness with Bud Lite. Rhetoric has three components: logic, morals, and ethics (logos, pathos, ethos) and "lie" is possible in each or any combinations of these dimensions of argument, and comedy as well. (I show how this works in my book).