I work as a customs officer and meet many foreigners daily.

officer 是名词，来自动词 officiate（执行公务）的词根 offic-（表示"公务、职责"）加上后缀 -er（表示"执行...的人"），指"官员、公务员"。 customs officer 特指在海关工作的公务人员，负责检查出入境人员和货物。