(not) bat an eye/eyelash/eyelid

to not show any shock or surprise.

'So what did she say when you told her you were leaving?' 'She didn't bat an eyelid.'

• hang a left
• hang a right
• hang around
• hang back
• hang by a thread
• hanger-on
• hang fire
• hang hat on
• hang hat on something
• hang head
• hang head in shame
• hang in the balance
• hang in there
• hang it up
• Hang loose!
• hang on
• Hang on a mo.
• hang on by your fingertips
• hang on every word
• hang on for dear life
• hang on in there
• hang on like grim death
• hang on someone's every word
• hang onto
• hang on to for dear life