I just like the way this word sounds–it’s fun to say! 🙂
Dubious [doo-bee-uh s] is an adjective meaning “doubtful” or “questionable”, from the Latin word dubius. Pretty straightforward there.
The other parts of speech that owe their existence to the word dubious are great, too! Like the noun superdubiousness. I can never see it being used, but that’s okay.
I actually use the word dubious (or perhaps more often its adverb counterpart, dubiously) quite often in my writing.