Paralysis is the inability to move part of your body. It's actually fairly common for people to have short periods of paralysis while they sleep.
Paralysis is the experience of being paralyzed, or unable to move part or all of your body. There are medical conditions that can cause paralysis. You can also use paralysis to describe the inability to act, like the paralysis of a city during a big snowstorm, or the paralysis of the school play's star, suddenly struck with stage fright.