shenanigan
Dishonest, underhanded, or unscrupulous activities or behaviour; skulduggery, trickery; also, mischievous behaviour or play; high jinks.
dated, informal, rare, uncountable
One of Professor [John] Moon's most astonishing "experiments," consisted of holding a watch suspended from a short chain at arm's length, and allowing anyone in the pit to pull pistol and "blaze away" at the word "fire," whereupon the watch would most unconscionably disappear. An individual who had attended several evenings and witnessed the "experiment," suspected, in the classic language of the times, that there was something of "shenanigan" in it.
Where it comes from
The origin of the noun is uncertain. As the earliest attestations are from California, U.S.A., in the 1850s towards the end of the California gold rush (see the quotations), it is possible that the word derives from one of the following: * Irish sionnachuighim (“to play tricks”, literally “to play the fox”); Irishmen were among the people participating in the gold rush. (See also the 31 December 1854 quotation suggesting it is an “Irish word”.) * Spanish chanada, a shortening of charranada (“deceit, trick”); California was colonized by the Spanish Empire in the 18th century, and many people from Latin America also took part in the gold rush. Other suggestions are set out in the table below. possible etymologies * From the East Anglian dialectal word nannicking (“playing the fool”). * From French ces manigances (“these fraudulent schemes”). * From German Scheinheilige (“sham holy men;
Adapted from the Wiktionary entry shenanigan (CC BY-SA 4.0).