变质
biàn zhì · HSK 7
to go bad
🧫 biàn zhì = change + quality — quality changed, it went bad
变 means change, 质 means quality or substance. When the quality of something changes for the worse, it degenerates or spoils. Think of milk left out: its quality shifts — biàn zhì, gone bad.
变 — top 䜌 (phonetic) + bottom 又 (hand)
Originally written 變, a phonosemantic compound: 䜌 (luán) gives the sound while 攵 (a hand with a stick) suggested the action of changing or transforming. The simplified form 变 keeps the phonetic top in reduced shape over 又 (hand). Core meaning: to change, transform, or alter.