Source : Webster's Revised Unabridged Dictionary (1913)

Shrill \Shrill\, v. i. [imp. & p. p. {Shrilled}; p. pr. & vb. n.
   {Shrilling}.] [OE. schrillen, akin to G. schrillen; cf. AS.
   scralletan to resound loudly, Icel. skr["o]lta to jolt, Sw.
   skr["a]lla to shrill, Norw. skryla, skr?la. Cf. {Skirl}.]
   To utter an acute, piercing sound; to sound with a sharp,
   shrill tone; to become shrill.

         Break we our pipes, that shrilledloud as lark.
                                                  --Spenser.

         No sounds were heard but of the shrilling cock.
                                                  --Goldsmith.

         His voice shrilled with passion.         --L. Wallace.

Source : WordNet®

shrilling
     adj : continuous and piercing; "clashing swords and shrilling
           trumpets" [syn: {shrilling(a)}]
     n : a continuing shrill noise; "the clash of swords and the
         shrilling of trumpets"--P. J. Searles