Someone told me it was someone who farts so hard that they knock things over. I don't think any of us really know what it means.
(both kevin and John don't know what a fart knocker is)
Kevin: You're a fart knocker
John: What's a fart knocker?
Kevin: You don't know what a fart knocker is?!
John:...oh...yeah, of course I know what a fart knocker is.
1. a trained doctor who knocks the farts right out of you.
2. a person/thing who knocks the farts out of you with a quick blow to the stomach
3. a dumbass who thinks he's cool but he's trip'n
1. Dr. Fart knocker used a Fart knocking device to knock the farts out of little Tony.
2. Rover knocked the farts out of his owner when he wanted to play "fetch"
3. Elmo's gonna knock the farts out of you!