税务
shuì wù · HSK 7
service
🧾 税 tax + 务 affairs = the tax-affairs office; shuì wù sounds like shway-woo
税 means tax and 务 means affairs or duties (same 务 as in 服务 service). Together: the government body handling tax affairs. The wù in shuì wù is the duty-business morpheme that recurs across official service words.
税 — grain radical 禾 + 兑 (exchange/phonetic)
税 combines 禾 (grain) with 兑 (exchange), which also hints at the sound. In ancient China taxes were paid in grain, so the character originally meant a levy of harvest given to the state. Its meaning later broadened to taxes and duties of any kind.