noun, noun which may take the genitive case particle 'no', na-adjective
tone deafness; amusia; having no ear for music
Refers to the inability to perceive or reproduce musical pitch accurately. Can be used as a noun or adjectivally (音痴な人, 音痴の).
彼は音痴だから、カラオケに行くのを嫌がる。
He's tone-deaf, so he hates going to karaoke.
音痴な人でも楽しめる音楽ゲームがある。
There are music games that even tone-deaf people can enjoy.
noun, used as a suffix
having no sense of; being hopeless at; -illiterate
Suffix attached to nouns indicating a lack of skill, sense, or aptitude in that area. Common examples: 方向音痴 (no sense of direction), 機械音痴 (hopeless with machines), 運動音痴 (athletically challenged).
私は方向音痴で、すぐ道に迷ってしまう。
I have no sense of direction and get lost easily.
父は機械音痴で、スマホの操作も苦手だ。
My father is hopeless with machines and struggles even with smartphone operation.
Compound of 音 (sound, music) and 痴 (foolish, stupid). The suffix usage extends the idea of 'tone-deaf' metaphorically to other domains.