A word that means outdated tradition

I remember watching an episode of Good Mythical Morning on YouTube the other day, and they had a game where they were given words and had to guess what they meant. One of the word's definition roughly meant outdated traditions or traditions that no longer make sense in the context of the modern-day but that we still perform.

I can't find the video now, and it's bothering me so much that I can't find this word. I've tried googling and nothing relevant is showing up.

Mumpsimus. Here is the episode: https://www.youtube.com/watch?v=z-d7IK0mHMA

And here is the evidence https://www.dictionary.com/browse/mumpsimus?s=t