someone in the act of being a hobknocker: a hobknocker is someone that runs around and rubing there penis and balls on random people and , or kicking random people in the balls
example: kate ann sailor kicking people in the balls or rubbing her balls over a random person. this is what a hobknocking person does.
"Hobnocker" is a completely made up word from the nickelodeon show iCarly.
All of the previous definitions were written to Urban Dictionary AFTER the episode of iCarly with the meaningless word aired early 2009, all of the previous comments being a little bit later on.
The only description (from the episode of iCarly) is "gross... and illegal"