David M. Allen said this quote

“ Invalidating someone else is not merely disagreeing with something that the other person said. It is a process in which individuals communicate to another that the opinions and emotions of the target are invalid, irrational, selfish, uncaring, stupid, most likely insane, and wrong, wrong, wrong. Invalidators let it be known directly or indirectly that their targets views and feelings do not count for anything to anybody at any time or in any way. ”