I learned about this word today too. It stands for 'Joy Of Missing Out".
You were thinking of buying a coin and later that coin dumps to oblivion. That's JOMO!
My first time to hear this, JOMO, lol.
Even it is my first time but I already experienced this multiple times. But before that, before we JOMO, we are somehow clueless or have no idea at all. But sometimes you are thankful you didn't enter on that trade and that's JOMO.