trembles

(noun) disease of livestock and especially cattle poisoned by eating certain kinds of snakeroot. Synonyms: milk sickness.

(noun) a reflex motion caused by cold or fear or excitement. Synonyms: tremble, shiver, shake.

(verb) move or jerk quickly and involuntarily up and down or sideways. Synonyms: tremble. Example: "His hands were trembling when he signed the document."