Other forms: spastics; spastically
A spastic motion is jerky and convulsive. This word also applies to people suffering from spastic paralysis.
Have you ever had a muscle spasm? Then you know what it's like to have a muscle move jerkily on its own. That kind of unpredictable, uncontrolled movement is called spastic. Anyone could have a spastic muscle briefly, but some people have spastic paralysis, in which their muscles are permanently out of their control and difficult to use. People with this condition have sometimes been called spastics, but that term is now offensive and should be avoided.