一本正经

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

CEDICT

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

Wiktionary

一部正规的经典。形容人态度庄重认真。

重編國語辭典

  1. 形容人态度庄重认真
  2. 面无表情

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 正经 zhèngjīng
  1. decent
  2. honorable
  3. proper
  4. serious
  5. according to standards