HODL (hold on for dear life)
The typo from the English word HOLD has become popular - it means long-term holding, i.e. if someone HODLS cryptocurrency, they want to own it in the long run. So they do not plan to trade it in the near future because they believe in long-term growth. In English, the words HOLD/HODL, and HOLDING /HODLING sound very similar, and perhaps that's why this funny typo has become a common concept.