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!
Hahahahaha! I currently only buy, and HODL Bitcoin. I have not felt the JOMO feeling in a very very long time. There was a few months when I was in my days as a "day-trader" that I felt that very laughable feeling. I believe there are JOMO feelings everywhere during the current stage of the market.