They reluctantly accepted the new regulations.

reluctantly 是副词，由形容词 reluctant（不情愿的）加上后缀 -ly 构成。reluctant 来自拉丁语 reluctari（抵抗、反对），表示"不愿意做某事"的状态。reluctantly 描述动作时带有"不情愿地""勉强地"的意味。