scal·a·wag Pronunciation Key (skl-wg) also scal·ly·wag (skl-) n. Informal. 1. A reprobate; a rascal, a scoundral 2. A person, esp a child, who behaves badly but in a harmless way. 3. One who is playfully mischievous E.g. You naughty little scallywag!