The company's profits have been in decline for the past few years.

decline 是动词，意思是"下降、衰退"，这里用作名词形式表示"下降的趋势"。这个词来自拉丁语 declinare，由 de-（向下）和 clinare（倾斜）组成，字面意思是"向下倾斜"，引申为"衰退、减少"。