Source : Webster's Revised Unabridged Dictionary (1913)

Shrilly \Shril"ly\, adv.
   In a shrill manner; acutely; with a sharp sound or voice.

Shrilly \Shril"ly\, a.
   Somewhat shrill. [Poetic] --Sir W. Scott.

         Some kept up a shrilly mellow sound.     --Keats.

Source : WordNet®

shrilly
     adv : in a shrill voice; "she sang rather shrilly" [syn: {piercingly}]