The concept of lightgassing , as proposed by Spencer Greenberg: Affirming someone’s known-to-be false beliefs or statements in order to be supportive (or, I would add, to avoid making them angry or incur favor, which is also common). As Spencer notes, the key is often to validate someone’s feelings, without validating their false beliefs. Having a name for this might be useful, so people can request others avoid it, or explain why they are not doing it.