Is the word lone a verb?

No, "lone" is not a verb. It is an adjective meaning "being alone" or "being the only one".

Here are some examples:

* Lone wolf: A person who prefers to work or live alone.

* A lone tree: The only tree in a vast field.

* A lone traveler: A person traveling alone.

If you're looking for a verb that means to be alone, you might use "isolate" or "separate".