Source : Webster's Revised Unabridged Dictionary (1913)

Waul \Waul\, v. i. [Of imitative origin.]
   To cry as a cat; to squall; to wail. [Written also {wawl}.]

         The helpless infant, coming wauling and crying into the
         world.                                   --Sir W.
                                                  Scott.

Source : WordNet®

waul
     v : make high-pitched, whiney noises [syn: {squall}, {wawl}]