The Collaborative International Dictionary of English v.0.48:

Noddy \Nod"dy\, n.; pl. Noddies. [Prob. fr. nod to incline the
   head, either as in assent, or from drowsiness.]
   1. A simpleton; a fool. --L'Estrange.

   Syn: tomnoddy.
        [1913 Webster]

   2. (Zool.)
      (a) Any tern of the genus Anous, as Anous stolidus.
      (b) The arctic fulmar (Fulmarus glacialis). Sometimes
          also applied to other sea birds.
          [1913 Webster]

   3. An old game at cards. --Halliwell.
      [1913 Webster]

   4. A small two-wheeled one-horse vehicle.
      [1913 Webster]

   5. An inverted pendulum consisting of a short vertical flat
      spring which supports a rod having a bob at the top; --
      used for detecting and measuring slight horizontal
      vibrations of a body to which it is attached.
      [1913 Webster]