tremble

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To shake involuntarily, as from excitement or anger; quake. See Synonyms at shake.
2. v. To feel fear or anxiety: I tremble at the very thought of it.
3. v. To vibrate or quiver: leaves trembling in the breeze.
4. n. The act or state of trembling.
5. n. A convulsive fit of shaking. Often used in the plural with the.
6. n. An infectious viral disease of sheep that is transmitted by the tick Ixodes ricinus and affects the nervous system, causing galloping and trotting by little leaps and often prolonged trembling. Also called louping ill.
7. n. Poisoning of domestic animals, especially cattle and sheep, caused by eating white snakeroot or rayless goldenrod and characterized by muscular tremors and weakening. Also called milk sickness.

Century Dictionary and Cyclopedia

1. To be affected with slight, quick, and continued vibratory movements; be moved in a quivering manner by some external force.
2. To be affected with involuntary muscular agitation; be agitated convulsively from either a physical or a moral cause; be in a tremor; quake; shake: as, to tremble with fatigue; his hand trembled from excitement.
3. To feel or manifest a quivering agitation; be tremulous or shaky; quiver; quaver: as, his voice trembled from emotion.
4. Figuratively, to be in doubt or suspense; oscillate between certainty and uncertainty; hang upon chance.
5. n. The act or state of trembling; an involuntary quivering or shivering as from cold or fear.
6. n. plural A form of disease or diseased condition in man or animals, characterized by continued trembling or tremulousness; specifically, in some parts of the United States, a disease of domestic animals, under peculiar local conditions, affecting the quality of the milk and flesh, and known as milk-sickness when communicated through these to human beings. See milk-sickness.

Wiktionary

1. v. intransitive To shake, quiver, or vibrate.
2. n. A shake, quiver, or vibration.

GNU Webster's 1913

1. v. To shake involuntarily, as with fear, cold, or weakness; to quake; to quiver; to shiver; to shudder; -- said of a person or an animal.
2. v. To totter; to shake; -- said of a thing.
3. v. To quaver or shake, as sound; to be tremulous; as the voice trembles.
4. n. An involuntary shaking or quivering.

WordNet 3.0

1. n. a reflex motion caused by cold or fear or excitement
2. v. move or jerk quickly and involuntarily up and down or sideways