Laura stepped into her boss's office, wished him a Merry Christmas, and resigned.

resigned 是动词 resign 的过去式，resign 的意思是"辞职、放弃职位"。这个词由前缀 re-（表示"再次"或"离开"）和 sign（签署）组成，字面意思是"再次签署"或"解除签署"，引申为"放弃职位"。