merriment n gaiety, fun, or mirth
This is a little fun word that I found in this Aeon article. Obviously it comes from the word merry which (less transparently) itself derives from agreeable.
Why fun? Perhaps because it is not so used, it is passé (according to Google Ngram, it is 5 times less common than early 19th Century) and there is an attraction for things of the past, even words.
So let’s add some merriment in our lives, some well-deserve joy and gaiety, and if we can, a little frivolity – another of these words from the past.