shrill 
(shrĭl)
(shrĭl)adj. shrill·er, shrill·est
1. High-pitched and piercing in tone or sound: the shrill wail of a siren.
2. Producing a sharp, high-pitched tone or sound: a shrill fife.
3. Sharp or keen to the senses; harshly vivid: shrill colors.
v. shrilled, shrill·ing, shrills
v.tr.
To utter in a shrill manner; scream.
v.intr.
To produce a shrill cry or sound.
[Middle English shrille.]
shrillness n.
shrilly adv.