noun a shrill sound.
2. shrill ·vt to utter or express in a shrill tone; to cause to make a shrill sound.
3. shrill ·vi to utter an acute, piercing sound; to sound with a sharp, shrill tone; to become shrill.
4. shrill ·vi acute; sharp; piercing; having or emitting a sharp, piercing tone or sound;
said of a sound, or of that which produces a sound.