shrill
v.v. to make a loud, high-pitched, and unpleasant sound. You use this when someone is screaming or when a machine is making a very annoying noise.
v. to produce a high-pitched, piercing, and often unpleasant sound. Intransitive — typically describes the sound of a voice or a mechanical device.
The alarm started to shrill in the middle of the night.
The angry crowd began to shrill as the politician refused to answer their questions.
As the pressure in the reactor continued to rise, the safety valves began to shrill, signaling an imminent failure that required immediate evacuation.
From Late Middle English schrille, shirle, shrille (“of a sound: high-pitched, piercing; producing such a sound”), possibly from the earlier shil, schille (“loud, resounding; high-pitched”), from Old English scill (“sonorous sounding”), of Germanic origin and probably ultimately imitative. The r in the word was introduced by analogy to Middle English skrīke, skrīken, scrēmen, possibly to avoid confusion with non-Anglian forms of schelle (modern English shell) where Old English scill (“sonorous sounding”) and scill (“shell”) existed. The word is cognate with Icelandic skella (“crash, bang, slam”), Low German schrell (“sharp in taste or tone”).