He warned his friend that the girl might be a gold-digger since she kept asking about his income during their dates.

gold-digger 是由 gold（黄金）和 digger（挖掘者）组成的复合词。gold 象征财富和金钱，digger 指"挖掘的人"。 gold-digger 字面意思是"挖掘黄金的人"，引申为"拜金者"，特指为了金钱而追求异性的人，通常带有贬义。