Source : Webster's Revised Unabridged Dictionary (1913)

Booby \Boo"by\ (b[=oo]"b[y^]), n.; pl. {Boobies} (-b[i^]z). [Sp.
   bobo dunce, idiot; cf. L. balbus stammering, E. barbarous.]
   1. A dunce; a stupid fellow.

   2. (Zo["o]l.)
      (a) A swimming bird ({Sula fiber} or {S. 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. The name is also sometimes
          applied to other species of gannets; as, {S.
          piscator}, the red-footed booby.
      (b) A species of penguin of the antarctic seas.

Booby \Boo"by\ (b[=oo]"b[y^]), a.
   Having the characteristics of a booby; stupid.

Source : WordNet®

booby
     n 1: an ignorant or foolish person [syn: {dumbbell}, {dummy}, {dope},
           {boob}, {pinhead}]
     2: small tropical gannet having a bright bill or bright feet or
        both