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).
Scientists get to choose what terminology they use to discuss scientific topics among themselves. Philosophers get to do likewise. Every philosophy class I have taken and every source I have looked up has the same definition for 'valid'. A definition which differs from yours.
I choose the definition generally agreed on by the entire philosophical community rather than a single individual who now appears to have some sort of axe to grind.
Are you upset at the direction philosophy has taken? Even modern day Thomists would agree with the distinction between valid and sound that I have merely repeated. Here is an example of a tenured Thomist philosopher working his way through an argument that he quickly determines is valid, but requires additional reasoning to show its soundness: