Some of my students made up a new word today, accidentally: mysterical. They define it as ‘When you don’t know why you’re laughing’. Having googled it, of course it turns out that others have come up with the word before, but this definition is way better than those in the Urban Dictionary.
[Edit: at their insistence can I just add that A Ri and Min Jeong made the word up and Soon Hyeong defined it. Please use the word copiously until it is the most famous English word ever. Thank you.]