necker Ask Urban Dictionary about necker Share definition Flag the art of slapping someone on the knape of their neck with the back of your hand. if done properly, it will sting and piss that person off. Holy shit he just gave Brandon Wiggan a necker! necker by Bobby Hoag September 23, 2008 0 0 necker Merch Get the necker mug. Buy Now — $32.95 See more merch