吹毛求疵

chuīmáoqiúcī
  1. lit. to blow apart the hairs upon a fur to discover any defect (idiom); fig. to be fastidious
  2. nitpick

CEDICT

to nitpick; to pick holes; to cavel at

Wiktionary

吹开皮上的毛，寻找裡面的小毛病。语本《韩非子．大体》：「不吹毛而求小疵，不洗垢而察难知。」后比喻刻意挑剔过失或缺点。《汉书．卷五三．景十三王传．中山靖王刘胜传》：「有司吹毛求疵，笞服其臣，使证其君。」也作「吹毛求瑕」、「吹毛取瑕」、「吹毛索疵」。

重編國語辭典

刻意挑剔过失或缺点

維基詞典

Entry Composition

1 吹 chuī
  1. to blow
  2. to play a wind instrument
  3. to blast
  4. to puff
  5. to boast
  6. to brag
  7. to end in failure
  8. to fall through
2 毛 máo
  1. hair
  2. feather
  3. down
  4. wool
  5. mildew
  6. mold
  7. coarse or semifinished
  8. young
  9. raw
  10. careless
  11. unthinking
  12. nervous
  13. scared
  14. (of currency) to devalue or depreciate
  15. classifier for Chinese fractional monetary unit ( = 角 jiǎo , = one-tenth of a yuan or 10 fen 分 fēn)
3 求 qiú
  1. to seek
  2. to look for
  3. to request
  4. to demand
  5. to beseech
4 疵 cī
  1. blemish
  2. flaw
  3. defect