expressionless
adj. 无表情的；呆板的
例句
Her voice was flat and expressionless.
她的声音平淡而呆板。
《牛津词典》
His face was expressionless, but Alex felt the unspoken criticism.
他面无表情，但亚历克斯感觉到了他无言的批评。
《柯林斯英汉双解大词典》
His face had become peculiarly expressionless.
他的脸变得异乎寻常地毫无表情。
