General:
* Convulsions: This term is often used for more severe spasms, particularly those involving the whole body.
* Twitches: This word refers to small, involuntary muscle contractions.
* Contractions: This term is more medical and can be used for both voluntary and involuntary muscle contractions.
* Seizures: This word is used for sudden episodes of involuntary muscle contractions, often associated with neurological conditions.
Specific to body parts:
* Cramps: Used for painful spasms in muscles, especially in the legs or abdomen.
* Tremors: This refers to rhythmic, involuntary shaking, often in the hands or head.
* Tic: A sudden, repetitive, involuntary movement, often involving a specific muscle group.
* Myoclonus: This is a more medical term for brief, involuntary muscle contractions.
Other:
* Jerks: This word is used for sudden, involuntary movements.
* Fits: This is a general term for seizures or other sudden episodes of involuntary movements.
The best synonym to use will depend on the specific situation and the severity of the spasms.