trem·ble 
(trĕmbəl)
(trĕmbəl)intr.v. trem·bled, trem·bling, trem·bles
1. To shake involuntarily, as from excitement or anger; quake. See Synonyms at shake.
2. To feel fear or anxiety: I tremble at the very thought of it.
3. To vibrate or quiver: leaves trembling in the breeze.
n.
1. The act or state of trembling.
2. trembles A convulsive fit of shaking. Used with the.
3. trembles (used with a sing. verb)
a. Poisoning of domestic animals, especially cattle and sheep, caused by eating white snakeroot or the composite plant Isocoma pluriflora of the southwest United States and northern Mexico, and characterized by muscular tremors and weakening. Also called milk sickness.
b. Any of several other animal diseases characterized by trembling, such as louping ill.
[Middle English tremblen, from Old French trembler, from Vulgar Latin *tremulāre, from Latin tremulus, trembling; see TREMULOUS.]
trembler n.
trembling·ly adv.
trembly adj.