a base, dishonest, or unscrupulous person.

a mischievous person or animal

That child is a real rascal.

noun

beggar , blackguard , black sheep * , bully , bum , cad , cardsharp , charlatan , cheat , delinquent , devil , disgrace , felon , fraud , good-for-nothing * , grafter , hooligan * , hypocrite , idler , imp , liar , loafer , mischief-maker , miscreant , opportunist , pretender , prodigal , profligate , recreant , reprobate , robber , rowdy , ruffian , scamp , scoundrel , sinner , skunk * , sneak * , swindler , tough * , tramp , trickster , varmint , villain , wastrel , wretch , prankster , rogue , caitiff , dog , knave , ne\'er-do-well , rake , rapscallion , renegade , ribald , scalawag , scapegrace , scaramouche , tough , troublemaker , varlet