unperturbed

/ˌʌn.pɚˈtɝːbd/

形容词

（尤指在意外情况下）不担忧的；镇静的；平静的
He seemed completely unperturbed at the idea of having to sing in a room full of strangers.
他似乎一点都不担心在一屋子陌生人面前唱歌。