Jimjams - Slang. extreme nervousness; jitters. Origin: Jimjams is a gradational compound based on the word jam meaning "to press, squeeze, or fill tightly." The sense “nervous jitters” entered English in the 1800s.
Jitterbug dance contest, San Francisco, c. 1940s "The term jitterbug comes from an early 20th-century slang term used to describe alcoholics who suffered from the "jitters" (i.e., delirium tremens).The term became associated with swing dancers who danced without any control or knowledge of the dance. In popular culture, it became generalized to mean swing dancers themselves (jitter bugs), or a type of swing dance – "they danced the jitterbug"
Swing dancers are often referred to as jitterbugs because they dance without any control like an alcoholic who suffers from the ‘jitters’. It can also mean a type of Swing dance or the act of Swing dancing. In 1934, Cab Calloway recorded Call of the Jitter Bug and the film Cab Calloway’s Jitterbug Party which popularised the word.