What is the difference between a muscle spasm and a muscle cramp?

Spasm vs cramp. Muscles in our body contract and relax consciously and unconsciously. A muscle that involuntarily contracts without our consciously willing it is called a "spasm." if the muscle maintains a sustained "spasm", it becomes a cramp, as can be seen with exercise. The muscle cramp is thus an involuntarily and forcibly contracted muscle that does not relax despite our desire to relax the muscle.
Cramp more intense. Spasm comes on gradual and less intense. Cramps are very intense and come on suddenly. Cramps are extremely painful.