tremor

Short definition from Wiktionary

Noun

1. 1
   A shake, quiver, or vibration.
2. 2
   A shake, quiver, or vibration: A rhythmic, uncontrollable shaking of all or part of the body due to partial muscle contractions.
3. 3
   An earthquake.

Verb

1. 1
   To shake or quiver excessively and rapidly or involuntarily; to tremble.