not bat an eye

US /nɑt bæt ən aɪ/
UK /nɑt bæt ən aɪ/
"not bat an eye" picture
1.

眉一つ動かさない, 驚かない

to show no surprise or concern when something unusual or shocking happens

:
When she heard the bad news, she didn't bat an eye.
悪い知らせを聞いても、彼女は眉一つ動かさなかった
He told them he was quitting, and they didn't bat an eye.
彼が辞めると言っても、彼らは眉一つ動かさなかった