I'm not sure what you're looking for here. It really depends on what kind of shaking or trembling you're talking about. Is the word "convulse" or "convulsing" or "convulsion" what you're looking for?
quiver
Another word for shake is "Tremble".
The quiver holds arrows. Quiver also means "to shake or tremble."
Another word for shake is "Tremble".
Another word for vibrate or shake is tremble or quiver.
tremble.
Shake Tremble Jittery
I started to TREMBLE at the thought of going on that scary ride. Tremble- to shake in fear; shiver; feels scared at the though
Vibrate, shudder, tremor, jitters.
tremble
Shake
The definition of tremble to shake, or vibrate. Generally, this is associated with anxiety or fear. So, it is fairly easy to conclude that the antonyms to tremble are words like calm, or steady.