刀不磨要生锈，人不学要落后

刀不磨要生鏽，人不學要落後
dāobùmóyàoshēngxiù,rénbùxuéyàoluòhòu
(proverb) a blade will get rusty if it is not sharpened; a man will fall behind if he doesn't study

CEDICT

Entry Composition

1 刀 dāo
  1. (slang) (loanword) dollar
  2. classifier for sets of one hundred sheets (of paper)
  3. classifier for knife cuts or stabs
  4. (Internet slang) to bargain; to ask for a small discount (esp. on second-hand marketplaces)

classifier: 把
2 不 bù
  1. no; not so
  2. (bound form) not; un-
3 磨 mó
  1. to rub
  2. to grind
  3. to polish
  4. to sharpen
  5. to wear down
  6. to die out
  7. to waste time
  8. to pester
  9. to insist
4 要 yào
  1. to want; to need; to ask for
  2. will; shall; about to
  3. need to; should
  4. if (same as 要是 yàoshi)
  5. (bound form) important
5 生锈 shēngxiù
  1. (of metal) to rust; to become rusty
  2. (fig.) (of a skill etc) to get rusty; to deteriorate
6 人 rén person; people

classifiers: 個, 位
7 不 bù
  1. no; not so
  2. (bound form) not; un-
8 学 xué
  1. to learn
  2. to study
  3. to imitate
  4. science
  5. -ology
9 要 yào
  1. to want; to need; to ask for
  2. will; shall; about to
  3. need to; should
  4. if (same as 要是 yàoshi)
  5. (bound form) important
10 落后 luòhòu
  1. to fall behind
  2. to lag (in technology etc)
  3. backward
  4. to retrogress