jitters

The word 'jitter' emerged in American English in the 1920s, likely as an alteration of the earlier dialectal term 'chitter', meaning 'to shiver' or 'to chatter'. 'Chitter' itself has a long history, traceable back to Middle English 'chiteren', which is of imitative origin, mimicking the sound of rapid, repeated clicking or trembling. The plural form 'jitters' became a fixed colloquial noun describing a state of nervous agitation, famously entering wider usage through the phrase "the jitters" in the early 20th century. Its onomatopoeic roots in sounds associated with shivering effectively convey the physical sensation of anxiety.

The word 'jitters' is considered a simplex form in modern English. It functions as a plural noun derived from the verb 'jitter'.