she·nan·i·gan

(shə-năn'ĭ-gən)

A:
1. A deceitful trick; an underhanded act.
2. Remarks intended to deceive; deceit. Often used in the plural.

B:
1. A playful or mischievous act; a prank.
2. Mischief; prankishness. Often used in the plural.