Hold On for Dear Life.
This is a play on the idea of HOLD.
It is a strategy for holding one's coins through volatile markets no matter what. Cryptocurrency can see some major pullbacks, hence the dear life part. When the crypto bear comes out, it can feel like one's world is coming to an end.
Bitcoin
The idea of HODL was promoted by the early Bitcoin adopters. This was an asset unlike few we saw in terms of the volatility. Bitcoin became quickly known for its massive pullbacks during bear markets. There was also the flipside when the bull took hold. Both directions saw large moves.
One result of this was the high percentage of Bitcoin that was not moved out of wallets during certain periods. This is led by the stake Satoshi Nakamoto has which was the original mining coins. Many question whether this will ever be moved.
HODLers believe in the long term potential of the coin in terms of price. As markets head higher, they seek to take advantage. These are people who are looking where the network and, thus, the associated value capture token, a decade or more down the road.
The main idea is to not let short-term moves cause one to miss a long-term explosion.