His shallowness was revealed by his superficial answers to philosophical questions.

shallowness 是由形容词 shallow（浅的、肤浅的）加上名词后缀 -ness 构成的名词，表示"浅薄、肤浅"的性质或状态。shallow 本身指"水浅的"，引申为"思想、知识等不深刻的"。