shenanigan (n.)

"nonsense; deceit, humbug," 1855, American English slang, of uncertain origin. Earliest records of it are in California (San Francisco and Sacramento). Suggestions include Spanish chanada, a shortened form of charranada "trick, deceit;" or, less likely, German Schenigelei, peddler's argot for "work, craft," or the related German slang verb schinäglen. Another guess centers on Irish sionnach "fox," and the form is perhaps conformed to an Irish surname.