shudders

Shudder is a term that functions as both a noun and a verb in English. As a verb, it means to tremble or shake suddenly and violently, often in response to fear, cold, or a strong emotional or physical stimulus. As a noun, a shudder is a sudden tremor or convulsive movement of the body, or, by extension, a similar tremor in an object or structure.

Physiologically, shuddering involves rapid, involuntary muscle contractions, typically beginning in the spine or neck and spreading outward. It can accompany fear, revulsion, or pain, and is often contrasted with shivering, which is a rhythmic tremor primarily driven by cold or fever.

In literature and everyday speech, shudder is frequently used to convey a visceral reaction, for example, “a shudder ran through the crowd” or “she shuddered at the memory.” In technical contexts, shudder may describe a brief, jerky vibration in machinery or a building during an earthquake or malfunction.

The word derives from the verb shudder, with origins in Middle English and older Germanic roots. See also shiver, tremor, and convulsion for related notions of movement or tremor.