プログレッシブ和英中辞典(第３版)の解説
そらす【反らす】
bend
- 体を後ろに反らす
bend backward - 彼は胸を反らして相手を見据えた
He straightened himself up and glared at his opponent. - 彼は得意気に胸を反らした
He 「stuck out his chest [puffed up] with pride.