Source : Webster's Revised Unabridged Dictionary (1913)

Coot \Coot\ (k[=oo]t), n. [Cf. D. koet, W. cwtair; cwta short,
   bodtailed + iar hen; cf. cwtau to dock. Cf. {Cut}.]
   1. (Zo["o]l.)
      (a) A wading bird with lobate toes, of the genus {Fulica}.
          The common European or bald coot is {F. atra} (see
          under {bald}); the American is {F. Americana}.
      (b) The surf duck or scoter. In the United States all the
          species of ({[OE]demia} are called coots. See
          {Scoter}. ``As simple as a coot.'' --Halliwell.

   2. A stupid fellow; a simpleton; as, a silly coot. [Colloq.]

Source : WordNet®

coot
     n : slaty-black slow-flying birds somewhat resembling ducks