Wiktionary: shenanigan (plural shenanigans)
1. Trickery, games; skulduggery. To "call", "claim" or "declare" shenanigans is to rhetorically label something as officially deceitful, improper, or otherwise incorrect.
"The advertisement said it would cost $50 but they charged me $75 at the register. I declare shenanigans." The speaker passes off the statement as having some sort of implied official effect, but in reality, it is simply a complaint.
2. A deceitful confidence trick, or mischief causing discomfort or annoyance.
You should learn to spot their shenanigans and avoid being fooled.
3. Mischievous play, especially by children.
I like the third definition as a starting point.
