一字之師

一字之师
yīzìzhīshī
one who can correct a misread or misspelt character and thus be your master

CEDICT

a teacher of one word; one who can significantly improve the quality of another's writing by changing one word and thus becomes his teacher

Wiktionary

稱能改正或更動文句中一個字的老師。

重編國語辭典

稱能改正或更動文句中一個字的老師

維基詞典

Entry Composition

1 一字 yīzì in a row; in a line
2 之 zhī
  1. (possessive particle, literary equivalent of 的 de)
  2. him
  3. her
  4. it
3 師 shī
  1. teacher
  2. master
  3. expert
  4. model
  5. army division
  6. (old) troops
  7. to dispatch troops