The magician is famous for being six-fingered on both hands.

six-fingered 是由数词 six（六）和名词 finger（手指）加上后缀 -ed 组成的形容词。six 表示数量"六"，finger 指"手指"，-ed 后缀表示"具有...特征的"。合起来 six-fingered 意思是"有六根手指的"，形容一个人每只手都有六根手指而非正常的五根。