若无其事

若無其事
ruòwúqíshì
(idiom) as if nothing had happened; calm and composed; nonchalant

CEDICT

calm; composed; uncaring; impervious; nonchalant

Wiktionary

好像没有那麽一回事。形容神态镇静、自然。

重編國語辭典

Entry Composition

1 若 ruò
  1. to seem
  2. like
  3. as
  4. if
2 无 wú
  1. not to have
  2. no
  3. none
  4. not
  5. to lack
  6. un-
  7. -less
3 其 qí
  1. his
  2. her
  3. its
  4. their
  5. that
  6. such
  7. it (refers to sth preceding it)
4 事 shì
  1. matter
  2. thing
  3. item
  4. work
  5. affair

classifiers: 件, 樁, 回