What does the root word fum means?

The root word "fum" doesn't have a widely recognized meaning on its own. It's more likely you're thinking of a related word or a variation of a root word.

Here are some possibilities and their meanings:

* "Fume" - This word, meaning "to give off smoke or vapor," is related to the Latin word "fumus" (smoke).

* "Fumigate" - This word, meaning "to disinfect by smoke or vapor," comes from the Latin word "fumigare" (to smoke).

* "Fumatory" - This word, meaning "relating to smoke or fumes," comes from the Latin word "fumus" (smoke).

Let me know if you had a different word in mind, and I'll be happy to help!