一本正經

一本正经
yīběnzhèngjīng
(idiom) in deadly earnest; deadpan

CEDICT

  1. absolutely serious; dead earnest
  2. deadpan; with a poker face

Wiktionary

一部正規的經典。形容人態度莊重認真。

重編國語辭典

  1. 形容人態度莊重認真
  2. 面無表情

維基詞典

Entry Composition

1 一本 yīběn
  1. (Mainland China, education) the first tier of universities
  2. (judo) ippon
  3. Used other than figuratively or idiomatically: see 一, 本 (běn).
  4. another version (terminology in collation)
  5. entirely based on
  6. having the same origin
  7. ippon
  8. the first tier of universities
2 正經 zhèngjīng
  1. decent
  2. honorable
  3. proper
  4. serious
  5. according to standards