ㄓㄥˋzhèngㄐㄧㄣjīnㄨㄟˊwéiㄗㄨㄛˋzuò

  1. 整理服裝儀容端正形容莊重嚴肅樣子史記·一二·褚少孫·日者》:賈誼瞿然正襟危坐。」·蘇軾赤壁賦〉:愀然正襟危坐何為?』」整襟危坐」。態度嚴肅搖頭擺腦

to sit upright and still (idiom)​