一日千里

yīrìqiānlǐ
lit. one day, a thousand miles (idiom); rapid progress

CEDICT

  1. (figurative) to develop rapidly; to make tremendous progress
  2. to develop rapidly; to make tremendous progress

Wiktionary

形容良馬跑得很快。語本《莊子．秋水》：「騏驥驊騮，一日而馳千里。」後比喻進步神速或事業發展得很快。《後漢書．卷六六．王允傳》：「同郡郭林宗嘗見允而奇之曰：『王生一日千里，王佐才也。』」

重編國語辭典

進步神速或事業發展快速

維基詞典

Entry Composition

1 一日 yīrì
  1. (literary or dialectal) one day
  2. (literary) another day in the future
  3. (literary) yesterday
  4. another day in the future
  5. one day
  6. yesterday
2 千里 qiānlǐ
  1. a thousand miles
  2. a thousand li (i.e. 500 kilometers)
  3. a long distance