Source : Webster's Revised Unabridged Dictionary (1913)

Pouter \Pout"er\ (-[~e]r), n.
   1. One who, or that which, pouts.

   2. [Cf. E. pout, and G. puter turkey.] (Zo["o]l.) A variety
      of the domestic pigeon remarkable for the extent to which
      it is able to dilate its throat and breast.

Source : WordNet®

pouter
     n 1: someone with a habitually sullen or gloomy expression [syn:
          {sourpuss}, {picklepuss}, {gloomy Gus}]
     2: one of a breed of pigeon that enlarge their crop until their
        breast is puffed out [syn: {pouter pigeon}]