His impressions of the boss are so funny that they always make the office colleagues laugh.

impressions 是名词 impression 的复数形式，impression 由前缀 im-（表示"进入"）和 press（压）组成，字面意思是"压入脑海的东西"，引申为"印象、感觉"。 在句中指"对某人或某事的看法或感受"，通常带有主观色彩。