Due to nervousness, there was a noticeable shakiness in his hands as he lifted the coffee cup.

shakiness 是名词，由形容词 shaky（颤抖的、摇晃的）加上名词后缀 -ness 构成，表示"颤抖的状态"或"不稳定的特性"。shakiness 在这里具体描述手部因紧张而产生的明显颤抖现象。