Fear of some sort which can cause a paralysis. An inability to move forward, or away from the stimulus of fear, Maybe we all experience some sort of nervousness, several examples could be stage fright, fear of speaking up for oneself in a difficult situation, moving out of the way of a rampaging animal or a speeding vehicle.
Other types examples could involve fear of being alone, thinking badly of oneself, or involuntary movements like shaking uncontrollably.
Fear is something we all feel at some time or other, but does it define us? Maybe, yes for some, not for others; each of us quietly determines a solution, if we can find it. Some can; others cannot and might feel trapped. Revolving around in a kind of endless vortex.