Hodl: The intentionally misspelled word hodl has its roots in a December 2013 post on the Bitcoin Talk forum, “I AM HODLING”; when the author, GameKyuubi, couldn’t be bothered to fix his typo, the community instantly turned it into a verb: to hodl. Along
with other terms, hodl is an effective litmus test for sussing out newcomers, carpetbaggers, and tourists.

Source: What Does Hodl Mean? A Glossary of Bitcoin Slang