1. blackguard, villain, scamp, scapegrace. Knave, rascal, rogue, scoundrel are disparaging terms applied to persons considered base, dishonest, or worthless. Knave, which formerly meant merely a boy or servant, in modern use emphasizes baseness of nature and intention: a dishonest and swindling knave. Rascal suggests shrewdness and trickery in dishonesty: a plausible rascal. A rogue is a worthless fellow who sometimes preys extensively upon the community by fraud: photographs of criminals in a rogues' gallery. A scoundrel is a blackguard and rogue of the worst sort: a thorough scoundrel. Rascal and rogue are often used affectionately or humorously (an entertaining rascal; a saucy rogue ), but knave and scoundrel are not.