[who_would_fardels_bear]

Mine is not an argumentum ad verecundiam. I'm merely defining terms. You use the words premise, logical, etc. which have specific meanings to philosophers. Similarly valid is a term used by philosophers to mean a specific thing.

Philosophers have been using valid and sound in the way mentioned at all of the links I pointed you to because it is useful to do so. It is useful to distinguish those arguments that are fallacious due to faulty premises from those that are fallacious due to faulty reasoning.

I don't know why you would want to conflate the two types of philosophical error. It serves no useful purpose.

[Olog-hai]

There’s a difference between defining terms and redefining terms. And using the appeal to authority for the purpose of supporting redefinition is characteristic of a deceptive argument—invalid and unsound (still synonyms).