HODL is a way of holding onto an investment, especially cryptocurrency, for a long time, even if the price goes up and down. It started as a typo on a Bitcoin forum years ago, from someone who meant to write "hold." People found it funny and it stuck, and now it stands for "Hold On for Dear Life." So, if you're a HODLer, you're basically saying you believe in the long-term value of your investment and you're not fazed by short-term price swings.
