Can refer to a device that shakes or trembles, or metaphorically to a person who shakes.
La tembladora en la mesa provocó que los vasos se movieran de un lado a otro.
The trembler on the table caused the glasses to move back and forth.
La tembladora en la mesa anunciaba una inminente tormenta que se acercaba.
The trembler on the table announced an imminent storm that was approaching.