Other forms: rascals
A rascal is a scoundrel or a trickster. If your new puppy cheerfully chews on your shoes and chases the cat, you might want to consider naming her Rascal.
Rascals are mischievous, but their intentions are to have fun, rather than to be cruel. An armed robber is not a rascal, but the class clown is a rascal. The word's origins had a more negative connotation, though: the fourteenth century rascaile meant "low class people," from the Old French rascaille, "rabble or mob."