Green’s Dictionary of Slang

jitters, the n.

[supposedly f. the Spoonerism ‘bin and jitters’ for ‘gin and bitters’ and orig. used of one who has drunk too much of that mixture]

1. [1920s+] extreme nervousness, a state of emotional and often physical tension, agitation.

2. [1930s–40s] (US) a hangover, delirium tremens.