noun, noun or participle which takes 'suru', intransitive verb
change in quality; alteration; deterioration
Refers to a fundamental change in the nature, quality, or character of something, often with a negative connotation of degradation or spoilage. Used for physical substances, abstract qualities, and personal character.
長期間の保存で油が変質した。
The oil deteriorated after long-term storage.
彼の性格は成功してから変質してしまった。
His character changed for the worse after he became successful.
noun
Specifically refers to abnormal or deviant sexual behavior or tendencies. Often used in psychological or legal contexts.
彼は変質者として警察に逮捕された。
He was arrested by the police as a sexual pervert.