冰凍三尺，非一日之寒

冰冻三尺，非一日之寒
bīngdòngsānchǐ,fēiyīrìzhīhán
three feet of ice does not form in a single day (idiom); Rome wasn't built in a day

CEDICT

Entry Composition

1 冰凍 bīngdòng to freeze
2 三 sān
  1. three
  2. 3
3 尺 chǐ
  1. a Chinese foot
  2. one-third of a meter
  3. a ruler
  4. a tape-measure
  5. one of the three acupoints for measuring pulse in Chinese medicine

classifiers: 支, 把
4 非 fēi
  1. to not be; not
  2. wrong; incorrect
  3. non-; un-; in-; de-
  4. to reproach; to blame
  5. (coll.) to insist on; simply must
5 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
6 之 zhī
  1. (possessive particle, literary equivalent of 的 de)
  2. him
  3. her
  4. it
7 寒 hán
  1. cold
  2. poor
  3. to tremble