1. A smelly kid, who never has marijuana, smokes, alcohol, or money to chill, always "bums" shit off you, like marijuana, smokes, alcohol, or money to go do sumthing or just to chill with you,
2. An outcast of the group, concluding himself as a smelly, poor kid.
NOTE: The subject that you may call a "ranky-bum" may also tend to be weird looking, ex. (ugly haircut, which would be a mushroom cut, fat wierd cheeks with a weird smile, deep wierd creepy, eerie voice, etc.)
1.JEREMY YOU Ranky-Bum
2.Shut up kid , it doesn't matter what you say, ur just a Ranky-Bum