twitch

A twitch is a small, sudden movement, often one that happens for just a moment. As a noun, it can mean a quick jerk or slight spasm in a muscle, such as an eyelid twitch when you have not slept enough. As a verb, it means to move in that quick way: a finger might twitch, a rabbit's nose might twitch, or someone's face might twitch with nerves.

The word is often used for movements that are not fully controlled. They may come from stress, tiredness, fear, pain, excitement, or a simple physical response. In everyday use, it often describes tiny movements in muscles, the face, or parts of an animal's body, especially when the movement is brief and easy to miss.

It can also describe a slight movement that shows feeling. A person's mouth may twitch before a smile, or a jaw may twitch with anger or tension. In this way, the word does more than name motion; it can hint at what someone is feeling inside.

Overall, the idea behind twitch is always quick, slight motion. Sometimes it is purely physical, and sometimes it helps paint a picture of emotion, nerves, or reaction, but it nearly always suggests a brief movement rather than a deliberate action.