Grok is a verb, meaning to understand something intuitively or by empathy. It was first used in the novel Stranger in a Strange Land by Robert Heinlein.

Grok has been adopted by the tech community for use when someone is very advanced at using a certain program or a command line utility, etc. When somebody gets to such an advanced level, they don’t just understand the program and it’s uses anymore, they grok it.

It’s actually kind of annoying and sad that Elon is stealing the word to use for his LLM.