Vibration (6)
I believe the answer is:
tremor
'vibration' is the definition.
(I know that tremor is a type of vibration)
This is the entire clue.
(Other definitions for tremor that I've seen before include "Small shock" , "A slight shake, perhaps of earth" , "Vibration - shaking" , "Shudder - quake" , "Nervousness" .)