重大
じゅうだい · juudai · JLPT N3 · na-adj
serious
⚖️ 重大 = heavy + big: a heavy, big matter is serious
重 (juu) means heavy and 大 (dai) means big. Something both heavy and big carries weight, so it is serious or important. The same 重 appears in 重要 (juuyou, important), and 大 in 大事 (daiji, important matter).
重 — person 人 + east 東 (phonetic)
Originally depicted a person carrying a heavy bundle on their back, suggesting weight and burden. The 東-like element served as a phonetic component. Over time the character split into two readings: zhòng meaning 'heavy' and chóng meaning 'repeat/again'.
大 — pictograph of a person with arms outstretched
大 is a pictograph showing a person standing with arms and legs spread wide. The outstretched arms suggest 'big' or 'great', extending from the literal image of a large stance to abstract meanings like important or grand. It is one of the oldest characters, found on oracle bones.