宵衣旰食

xiāoyīgànshí
  1. to dress before light and not eat before dark (idiom)
  2. diligently attending to official matters

CEDICT

Very hard-working.

Wiktionary

天未明就披衣起床，日暮才进食。形容勤于政事。《旧唐书．卷一九○．文苑传下．刘蕡传》：「任贤惕厉，宵衣旰食。」唐．陆贽〈兴元论解姜公辅状〉：「矧又时运方屯，物情犹鬱，乃是陛下握髮吐哺之日，宵衣旰食之辰。」也作「旰食宵衣」、「昃食宵衣」。

重編國語辭典

Entry Composition

1 宵 xiāo night
2 衣 yī
  1. clothes
  2. Kangxi radical 145

classifier: 件
3 旰 gàn
  1. sunset
  2. evening
4 食 shí
  1. to eat
  2. food
  3. animal feed
  4. eclipse