rascal; an idle worthless person
"The devil fetch ye, ye ragamuffin rapscallions; ye are all asleep. Stop snoring, ye sleepers, and pull." – Herman Melville, Moby Dick, 1851
"In his personal life [Christopher Hitchens] was no less the 'rapscallion iconoclast,' as historian Douglas Brinkley once described him. He left his pregnant first wife for another woman." – Elaine Woo, Los Angeles Times, December 15, 2011
About the Word:
There are no scallions in rapscallion. Rapscallion is an alteration of rascallion, which is itself an irregular formation of rascal, a term born in an Old French dialect word meaning "to scrape, clean off."
Source: Merriam-Webster's Top 10 charming words for nasty people