He was restless all night, tossing and turning due to work-related stress.

restless 由词根 rest（休息）和后缀 -less（表示"没有"）组成，字面意思是"无法休息的"。这个词形容人因为焦虑、紧张或兴奋而无法保持平静的状态，表现为坐立不安或频繁改变姿势。