What is the only shoresh in lashon hakodesh that starts with the letter "Vav"?
Nouns are fair game.
(Don't tell me there is more than one - Varod or Vered is Aramaic, and the shoresh of Vidui does not start with a "vav".)
Vav vav, which spells 'vav'? (I thought of this independently but confirmed it here.)