Sentence:  Once her <WSD>trembling</WSD> hand , with the pen grasped tight in it , was pressed against the paper the words came sharply , smoothly , as authoritatively as they would dropping from her own lips . 
Meaning of the word marked with <WSD> tags:  vibrating slightly and irregularly; as e.g. with fear or cold or like the leaves of an aspen in a breeze