noun
shrill sound; piercing noise; high-pitched grating sound
Describes a harsh, high-pitched, metallic or grating noise, often unpleasant to the ear. Commonly used for sounds like scraping metal, screeching brakes, or a piercing scream.
鉄板を引っ掻く金切り音が耳に痛い。
The shrill sound of scratching a metal plate hurts my ears.
急ブレーキの金切り音が駐車場に響いた。
The piercing screech of sudden braking echoed through the parking lot.
耳障り is an adjective meaning 'hard on the ears' or 'grating,' describing the effect of a sound, whereas 金切り音 is the sound itself.
Compound of 金切り (kanakiri, 'metal cutting') + 音 (on, 'sound'). The exact historical derivation is uncertain, but the term evokes the harsh, high-pitched noise produced when cutting metal.