miàn​bù​gǎi​sè

to not bat an eyelid

  1. face
    face; personal esteem or reputation; (bound form) look; appearance
  2. adverb
    not
    Negative adverb used before verbs, adjectives, and other adverbs to indicate negation; also used as a bound-form prefix to form terms with opposite meanings
  3. to change facial expression
    to change one's look or facial expression, often used in the context of remaining calm or showing fear