If “virtuous” is connected to “virtue,” then “vicious” must be connected to “vice.” Seems obvious in retrospect, but I never connected the dots before.
I did a quick lookup (after drying off), and sure enough, “vicious” and “vice” both derive from the Latin vitium, meaning a defect, fault, or blemish.
Go forth, freshly enlightened, and do with this knowledge what thou wilt.
Brian D. Buckley 
This is a really cool factoid. As silly as English is some days, you could easily have been wrong, though.
Let us not go to the dictionary … ’tis a silly place.