醋
cù · HSK 6
vinegar
🍶 酉 (wine jar) + 昔 (former/aged) — aged liquid in a jar = vinegar
The 酉 radical marks fermented liquids (wine, vinegar, sauce); 昔 means 'former' or 'long ago'. Vinegar is wine left too long. The 'jealousy' sense comes from 吃醋 (chī cù, eat vinegar) — a sour-feeling rival.
醋 — 酉 (wine jar) + 昔 (phonetic, formerly)
醋 combines 酉, depicting a wine vessel and signaling the meaning (fermented liquid), with 昔 serving as the phonetic component. Originally fermented drinks could turn sour, so the character came to mean vinegar. The 昔 element also hints at 'aged' or 'long ago,' fitting since vinegar results from prolonged fermentation.