I. -il(l)ē, -)li adverb
Etymology: shrill (II) + -ly
: in a shrill manner: as
a. : in a high-pitched voice or tone
the medics were whistling shrilly — R.O.Bowen
b. : in a high-strung, sharply insistent manner
protests a little too shrilly — Robert Payne
II. -ilē, -li adjective
Etymology: shrill (II) + -y
: somewhat shrill
a shrilly sound
parrots of shrilly green — W.W.Gibson