n. A dunce; a stupid fellow.n. n. A swimming bird (Sula fiber or Sula sula) related to the common gannet, and found in the West Indies, nesting on the bare rocks. It is so called on account of its apparent stupidity -- unafraid of men, it allows itself to be caught by a simple and undisguised approach. The name is also sometimes applied to other species of gannets; as, Sula piscator, the red-footed booby; and Sula nebouxii, the blue-footed booby.n. A species of penguin of the antarctic seas.adj. Having the characteristics of a booby; stupid.